Manchester United have made a pretty big splash in the transfer market this summer, bringing in young talents Ashley Young, David De Gea and Phil Jones to Old Trafford. But while these transfers may bring big dividends, the club has certainly had its fair share of big transfers.
Now aged over 100 years, Manchester United has thrived on a legacy of success, a tradition that has continued by bringing in some of the best players in the world through the transfer market.
So while the Red Devils gear up for their tour of the United States in which we will likely see some of these new fresh faces, here is a look back at the 15 most important transfers and signings in club history.
There's an old saying that goes "Offense sells tickets. Defense wins championships." In Tony Dunne's case, that defense brought an era of extreme success to Manchester United.
Sir Matt Busby brought Dunne to Old Trafford in 1960 for a fee of £5,000 from Shelbourne F.C. as a depth move to backup the full-backs Shay Brennan and Noel Cantwell.
However, Dunne's performance in the 1963 FA Cup Final made history and set him onto a career path that would see him garner 535 appearances for United as well as 33 caps for the Republic of Ireland.
His defense would also help Manchester United to two league titles as well as the 1968 European Cup championship.
It's extremely rare that a player spends more than one season at Old Trafford and doesn't win a major trophy.
However, Red Devils' legend Joe Spence did just that.
Spence was signed from the Northeast Amatuer club Scotswood in 1919 and quickly built up a reputation as one of the best United players between the two World Wars.
To this day his 168 goals still stands sixth all-time in the club's history and his 510 appearances is seventh all-time.
During his days, chants of "Give it to Joe!" were often heard throughout the ground as his footwork often dazzled the United supporters, who dubbed him with the nickname "Mr. Soccer."
However, Spence never won a major trophy with United as the club went through one of its least successful eras in history.
His career would not be devoid of any hardware though as his departure from Old Trafford landed him at Chesterfield, where he would win the Third Division North Championship in 1936.
Another popular expression in soccer is "The goalkeeper is the most important position in football." For years, Edwin Van Der Sar gave Manchester United trusted stability and solid play while wearing the odd-colored shirt.
Sir Alex Ferguson brought Van Der Sar to Manchester in 2005 when he signed him from Fulham for £2 million.
The 6'6" Dutch-born goalkeeper proved himself to be worth every penny, backstopping Manchester United to four Premier League titles, three FA Community Shields, one FA League Cup, one FIFA Club World Cup and a UEFA Champions League title.
While with United, Van Der Sar won the award for Best European Goalkeeper three times, and was named to the PFA Premier League Team of the Year.
Internationally, he was capped by the Netherlands 130 times, more than any other player in his country's history.
But perhaps one of his biggest accomplishments with United came in the 2008-09 season when he put together a shutout streak lasting 1,311 minutes, the Worldwide league record for clean-sheet keeping.
Van Der Sar also took one final record in his last appearance with United, becoming the oldest player ever to appear in the UEFA Champion's League at 40 years 211 days.
After just one year with the Red Devils, Javier "Chicharito" Hernandez might have already cemented his place as one of the most influential signings in Manchester United history.
In possibly one of his most shrewd moves, Sir Alex Ferguson conducted a deal with the young Mexican international in complete secrecy to bring him in for a fee of £10 million, which has proven to be one of the biggest bargains on this list.
In just one year, Hernandez has proven to be one of the most creative goal scorers in the world, scoring 20 times in his rookie season, leading to a nomination for PFA Young Player of the Year and recently winning the International Federation of Football History and Statistics "World Goalgetter 2011" title.
He's also proven he's got a flair for the memorable goals. Whether it was his first goal in a United shirt, a lobbing ball in the 2010 MLS All-Star Game (in which United became the first European team to defeat the American-league All-Stars) or his first competitive goal which rebounded in off his face, Chicharito likely has a long career ahead of him at Old Trafford.
It's often hard to tell just how great a player is going to be by looking at them while they are still young. Sir Matt Busby couldn't have imagined how solid and how consistent Bill Foulkes would be when he brought the young lad to Manchester United.
Manchester United scouts found Foulkes playing at the Whiston Boys Club in 1950 and just one year later Foulkes had signed his first professional contract with the Red Devils.
In a career that spanned from 1951-1970, Foulkes appeared in 556 matches for United, which to this day still stands third all-time on the club behind only Ryan Giggs and Sir Bobby Charlton.
However, he's most remembered for his tenacious defense, and his ability to lift his game to his opponents, relishing in facing some of the best scorers and forwards of his day.
He would occasionally pop in the dramatic tally of his own as well, scoring nine goals in his career, including the deciding goal of United's 1968 European Cup semi-final tie with Real Madrid off a George Best cross.
Foulkes also has the distinction of being a survivor of the Munich Air disaster, making his years at United that much more special.
It's very rare in any sport for a player to have two separate spells with the same team, but perhaps even more rare to do it with a club as elite as Manchester United, and perhaps even more rare than that to do better in that second spell.
Mark Hughes was initially signed by Manchester United in 1980 after a couple years in their youth program, however he did not make his first-team debut until 1983.
Hughes made himself worth the wait by scoring on his debut, however, and also added 25 goals in 55 games.
However in 1986 Hughes was sold to Barcelona for a price of £2 million.
After a failed first year with the Catalans, he was sent on loan to Bayern Munich, where he quickly regained his form and catching the eye of newly-appointed manager of Manchester United, Alex Ferguson.
Ferguson brought Hughes home to United in 1988 for £1.8 million, where he would stay and be a key part of the squad for the next seven years. He won the PFA Player of the Year title in his first season back in England, becoming the first Reds player to win the award.
In total, Hughes would score 163 goals for United in 467 games.
Without question going down as one of the biggest legends in the storied history of Manchester United, Paul Scholes will forever be remembered for his aggression, leadership and amazing ability to read a play and then make a perfect pass.
United didn't have to go far to find the red-headed Englishman, as he began training with the Manchester United Youth program at the age of 14.
In 1991, Scholes signed his first professional contract, bringing his fiery temper and amazing ball skills to the first team.
Throughout his career, Scholes was no stranger to discipline from both referees and governing bodies alike, however, amassing over 120 bookings his career and being sent off 10 times.
However, this aggression made him extremely solid defensively, often times jamming up opposing midfielders as they tried to distribute the ball through the middle of the field and causing poor passes and turnovers.
He played a very critical role filling in for a suspended Eric Cantona in the 1995-96 season, which caused him to see more and more time as a regular.
Paul Scholes retired at the end of this past season, having appeared in 676 matches and scoring 150 goals for the Red Devils.
Manchester United will be having a testimonial match in August 2011 to honor his 17-year career.
Despite the controversy around which he left United, there's a lot that can be said about the Dutch Striker.
Sir Alex Ferguson brought Van Nistelrooy to the Theater of Dreams in 2001, paying a hefty £19 million price to PSV Eindhoven.
In his first several years with United, he proved he was worth it.
In his first three seasons with Manchester United, Van Nistelrooy scored 100 goals, became the club's all-time leading scorer in European competitions in four seasons, and had reached the 150-goal plateau in five seasons and fewer than 200 starts. He twice scored in eight-consecutive games.
He even notched 44 goals in all competitions in the 2002-03 season and earned himself a PFA Player of the Year Award.
Despite his career with United going downhill quickly due to some alleged statements, Van Nistelrooy still goes down as one of the most prolific pure goal scorers and influential signings in Manchester United history, scoring 150 goals in 219 appearances in a United shirt.
Eric Cantona will certainly never be forgotten by football fans everywhere, particularly those lucky few who managed to anger him enough to the point where he did something to them.
Yes it's true, Cantona was quite the rebel in his time with the Red Devils, but there's no questioning that he had the skills to go with his attitude.
Cantona came to Manchester from Leeds United in 1992 for a fee of £1.2 million.
Despite numerous instances of being sent off, and even an extremely controversial flying kung-fu kick incident after a loss to Crystal Palace (that resulted in a prison sentence later turned down to community service), Cantona's place in the Manchester United lineup was never in doubt.
When he channeled this same aggression toward his football, the results were dazzling.
Cantona's skills saw him tally 82 goals in 185 matches for Manchester United, as well as a number of other intangibles that don't show up on the scoresheet such as offensive plays that often set up a number of goals from teammates.
His leadership and confidence also saw him named captain of Manchester United before the start of the 1996-97 season, after which he retired from professional football.
It's tough to pull someone away from the club they supported all through their childhood, but Manchester United managed to do that with Wayne Rooney, and he hasn't let them down since.
Rooney joined United from his boyhood club Everton for a fee of £25.6 million, at the time becoming the most expensive teenager in England.
Since then Rooney has been a regular member the Manchester United first team and is quickly moving his way up the all-time scoring list for the club.
Currently, Rooney already has 147 goals to his name in 322 appearances, and those numbers are only going to go up.
Rooney has proven he is a utility scorer for all occasions, scoring from just about anywhere at any time with even the narrowest window of opportunity.
Rooney had several key goals for United last season, including an overhead-volley in the 78th minute that lifted United to a 2-1 victory over Manchester City, and United's only tally in the Champions League Final drubbing by Barcelona.
With Rooney now locked up on contract until 2015, Rooney will only have more time to come to make his United legacy only grow stronger.
There are players who can score goals and then there are players that ever time they touch the ball it seems to wind up in the back of the opposition net. Denis Law was certainly one of those players.
And that statement could also be nothing further from the truth in the 1963-64 season when he netted a whopping 46 goals, to this day still a Manchester United record for a single season.
Law began his career with the second-division club Huddersfield Town before quickly catching the eye of Manchester City.
However, Law finally came to United after an unsuccessful year with Torino in Italy for a fee of £115,000, at the time a record transfer fee.
From there, Law would absolutely tear apart the competition around Europe, winning two First-Division Championships, an FA Cup, and a European Footballer of the Year Award in 1967.
Law's scoring records still stand as even today his 237 goals in a United shirt stand as the second-highest number of all-time behind only Bobby Charlton.
Law would eventually leave United for one more season at City, but even to this day the man who was "the Law" has a statue erected outside the entrance to the Stretford End Stand at Old Trafford to honor his greatness.
There are a lot of very high honors in the world of football, but Roy Keane has been bestowed with one that is unlike any other.
Keane has been described by Sir Alex Ferguson as the best player he has ever worked with.
And with the amazing talent that already been seen in this slideshow, that's really saying something.
Sir Alex brought Keane to Manchester United in 1993 for a record-setting £3.75 million transfer from Nottingham Forest, and Keane quickly made an impact.
Known for his fearless tackles, no-nonsense media presence, sharp tongue and unparalleled leadership in the locker room, Keane was the captain of Manchester United from 1997-2005.
It's very fitting that as a boy he became an avid fan of Bryan Robson, since Keane himself played in many ways a similar style of high-energy and high-aggression football.
This style also made him vicious on the pitch and led to a number of brutal fouls, send-offs and suspensions from just about every governing body in football.
However, despite this ungentlemanly conduct, Keane still managed to become the most successful captain in United history, leading them to nine major honors with him at the helm.
Teammate Darren Fletcher has been quoted as saying even though Keane is now gone from United, his influence and his work as a captain still lingers and is attributed to much of the success the Red Devils continue to have today.
Speaking of more shrewd business dealings from Sir Alex Ferguson...
Ryan Giggs was initially part of the Manchester City School of Excellence, and was on his way through the Manchester City youth program when Sir Alex Ferguson showed up at his home and convinced him to sign a professional contract with United.
This deal would prove to be one for the ages as Giggs has since gone on to become a living legend for Manchester United.
Now aged 37, Giggs is a near-automatic selection to start a game for United, and his consistency has seen him set several records.
The most important of which has to be one that was set on the night of Manchester United's most recent European triumph in Moscow. It was on that night that Giggs surpassed Sir Bobby Charlton by playing his 759th game in a Manchester United shirt.
Even more special on that night, it was Giggs who slotted home the winning penalty kick to give United the trophy.
Since then Giggs has gone on to become the most decorated player in English Football history, winning 12 Premier League champions medals, eight FA Community Shields, four FA Cups, three League Cups, and two UEFA Champions Leagues.
Giggs has also earned individual honors in being named the PFA Player of the Year, PFA Young Player of the Year (twice), a Sir Matt Busby Player of the Year award, and he was named the greatest United Player of all time in a poll by Manchester United's Magazine and website.
When George Best was initially scouted by Manchester United, Bob Bishop send a telegraph back to then-manager Matt Busby saying "I think I've found you a genius."
George Best would go on to become one of the greatest scorers, notching 179 goals in his Manchester United career.
But what really endeared him to the Manchester United fans was his showmanship and celebrity lifestyle.
Thanks in large part to that haircut, the Portuguese media dubbed him "O Quinto Beatle" meaning "The Fifth Beatle."
On the field Best scored spectacular goals and then celebrated them wildly.
Off the field, Best opened nightclubs, started fashion boutiques, and lived the lifestyle of a rockstar, developing problems with drinking, drugs and alcoholism.
While these did result in him more or less ruining his later career, fans would turn out in droves wherever he went to see him play, a testament to the quality he had created for his name.
There's a reason that Northern Ireland locals have developed the saying "Maradonna good; Pele better; George Best."
Without question the most influential player in the long history of Manchester United, Sir Bobby Charlton stands atop the history books as the highest scoring player ever to wear the red shirt.
Serving as captain of the squad from 1966-73, his 249 goals remain well out in front of any remaining active player, meaning this record is most likely safe for some time.
He was also capped by England 106 times, scoring 49 goals, also a record that still stands.
United acquired Charlton while he was just a lad at the East Northumberland School, bringing him in to the system at a young age and then keeping him there until 1973.
Charlton himself acquired a number of honors in his time with United, including winning an FA Cup, a European Cup, three First Division Championships, four Community Shield's, and several other individual accolades including being included on multiple lists as one of the best players of the last century.
However, one additional honor that Charlton earned that nobody else on this list has: Charlton was part of the England squad that captured the World Cup in 1966.
He also won the Golden Ball in that tournament as the most valuable player.
Perhaps what makes his legendary status even more hallowed is the fact that he, along with Bill Foulkes, was one of the Munich Air Disaster survivors.
Even though United were able to sign him while he was still a non-professional, his transfer to the squad was the most influential in the history, as his play with United has been firmly cemented in the football history books.