With new coaches, players and executives swirling into the league every year, the NFL is a business that is in constant flux.
While personnel may change as fast as any other industry, rivalries endure. But it is not just rivalries between teams that make the NFL even more interesting—tensions between different coaches and players add a whole new element to an already-thrilling game.
Here are the top rivalries in the NFL today.
This may be the most "popular" rivalry today for two main reasons.
First, both teams play a very similar style of football. They have excellent defenses year in and year out and have strong-armed quarterbacks to propel strong rushing attacks.
Their physical styles of play make for some of the hardest-hitting games all season.
Secondly, the games between these two have been extraordinarily close games—and not just in the regular season. These two teams met in the AFC Championship game in 2008 and the Divisional Playoffs in 2010.
What also makes this rivalry great is that, while they may want to knock the snot out of each other between the lines, there is a mutual respect between the two teams for how they play the game and how they compete with each other on such a high level.
This rivalry is just as fierce as the Ravens-Steelers rivalry but for entirely different reasons. The Ravens and Steelers have forged their rivalry based on on-field events and have a mutual respect for each other.
These two teams, on the other hand, hate each other like jealous sisters-in-law. This is not just a rivalry; there is genuine, deep hatred for both teams.
The Jets-Pats rivalry heated up about a dozen years ago when Bill Belichick resigned as "HC of the NYJ" on a napkin just a day after he was hired.
A year later, Mo Lewis' hit on Drew Bledsoe thrust Tom Brady into the starting job.
There have also been a ton of players and coaches to work for both teams. Curtis Martin followed Bill Parcells to the Jets. Shaun Ellis, a longtime Jet, spent his last year on the Patriots.
But it was not until 2007's "Spygate" incident in which then-Jets coach Eric Mangini ratted out his former mentor Bill Belichick in one of the biggest scandals in NFL history.
These two teams may not have the competitive and memorable games that the Ravens-Steelers rivalry has, but there is a hatred that runs deep between these two franchises.
For the first time in their long history, the Falcons and Saints are perennial Super Bowl contenders at the same time.
While the Panthers and Bucs have spent the last few years trying to find their way out of the bottom of the division, there is no question that both the Saints and Falcons have been the class of the division, with the Saints winning their first ring in 2009.
While they don't have nearly the same playoff success that the Saints have had, the Falcons have been remarkably consistent since Matt Ryan took over as quarterback. Since the Mike Smith/Matt Ryan era, the Falcon's worst record was 9-7 in 2009.
The once run-heavy Falcons are trying to emulate their New Orleans counterparts by becoming a more pass-first offense, making Matt Ryan, not Michael Turner, the centerpiece of their offense.
As long as Brees and Ryan are under center for their respective teams, this rivalry will endure.
Known as "the oldest rivalry in the NFL," this age-old clash between two "Black and Blue" division members is alive and well.
Except for, well, the whole "Black and Blue" part.
The Packers may feature the league's best passing attack, but they also gave up more yards on defense than any other team in the NFL.
The Bears certainly fit the description of "Black and Blue" better than the Packers, as they consistently field a solid defense under Lovie Smith. But even a franchise that is known for excellence on defense and special teams is looking to get better in the passing game with a quarterback as talented as Jay Cutler under center.
No matter what philosophy they employ, both teams should be right in the playoff mix come December.
Peyton Manning may be playing for a new team, but you had better believe that these two players still compare themselves to each other.
The Colts-Patriots rivalry was perhaps the best rivalry of the 2000s, as both teams were among the top teams in the AFC year after year. Because they would annually win their respective divisions, they faced each other every year—including some epic battles in the playoffs.
However, this is a rivalry, not spewing hatred between these two guys. Last year, Tom Brady said that "it sucks" to not have a healthy Manning playing football. As much as these two went at each other's defenses over the past decade, there is a ton of mutual respect between them.
As fate would have it, the Patriots play the Broncos in Week 5, so we will get to see these two face off at least one more time.
Just about every team in the NFC East is a big-time rival of each other, but the Giants-Eagles rivalry has been particularly heated over the past few years.
From DeSean Jackson's "Miracle at the Meadowlands II" to the fact that the Giants just won a Super Bowl during the Eagles' supposed "Dream Team" season, these two teams have been going back and forth during the Reid-Coughlin era.
This year, the Eagles are David to the Giants' Goliath. The Eagles brass is running out of patience to bring home a title, while Tom Coughlin will walk away from his job whenever he wants to—quite a stark contrast from a year ago.
This rivalry was assumed to be dead when Moss hung up his cleats last offseason, but now that he has returned to the NFL with the 49ers (who play the Jets in Week 3), Revis will get to face Moss at least one more time in his career.
Revis took offense to the notion that he was not as dominant as the stat sheet said:
Everybody saw the game, everybody knew I was in man coverage. He’s supposed to say that…
Exactly one year later, Randy Moss came up with a spectacular, one-handed catch over Revis, who was slowed down by a hamstring injury on the play.
Now that Moss is back in the NFL with the 49ers and on the Jets schedule this year, we should get to see at least one more Revis-Moss matchup before Moss hangs it up.
This old rivalry is being renewed as the Redskins find their way back to relevancy.
Based on RGIII's early returns in the season opener, Washington will be back in contention sooner than later.
Meanwhile, the Cowboys appear to making big strides of their own after knocking off the world champions in their own building on opening night—in rather decisive fashion.
There is no doubt that Dallas has been much more relevant as of late, but the Redskins have played the Cowboys very close in recent years. The Cowboys have won three in a row, but those have been very closely contested contests that could have gone either way.
Sure, the Cowboys may have the more "win-now" team, but as soon as RGIII figures out this NFL thing, this is going to be more like the rivalry in the 90s.
While this rivalry may be a relatively new phenomenon, only the Steelers are higher on the Ravens hit list than Tom Brady's Patriots.
It all started during the 2009 playoffs in which the Ravens dominated the Patriots on their home turf in the first round of the playoffs, paying them back for an earlier regular season loss on a questionable roughing the passer call.
This rivalry went to a whole new level after the Ravens suffered a heartbreaking loss to the Patriots in the 2011 AFC Championship game. The Ravens were just a Lee Evans catch away from representing the AFC in the Super Bowl, but their dreams were crushed when Billy Cundiff missed a chip-shot field goal to end the game.
Now that the Ravens have their quarterback in Joe Flacco, this rivalry will continue to grow as long as Brady is under center for New England.
Eli Manning has mastered the art of the poker face. Based on his facial expression, it is impossible to tell whether he just won the Super Bowl or just heard that his puppy died.
Occasionally, he will give the signature shoulder shrug, or when he's really mad, he will throw his hands in the air in amazement.
It is easy to make fun of Eli's borderline-creepy lack of emotion, but it definitely has served him well over the years.
Before he won his two Super Bowls, New Yorkers thought Eli just didn't care. The truth is Eli just never shows his emotional hand. Never getting too high or low from what happens on the field is truly the best way to survive in a city like New York.
The bad blood between these two franchises runs deep, as these two were AFC powerhouses back in the 1970s.
Since the turn of the century, both teams have been pretty irrelevant, but both franchises finally appear to be on the upswing.
The Chiefs, despite losing badly to the Falcons on Sunday, appear to finally have some direction. Meanwhile, the Raiders appear to be headed back toward relevancy with Reggie McKenzie running the show.
Despite the new faces in both organizations, the tension between these two is as fierce as ever, especially with the AFC West as wide open as it is this year.
It is a generally accepted fact that the Eagles would be a pretty darn good team—if Michael Vick could find a way to stay healthy.
Vick has dealt with injuries throughout his NFL career, including his days as a Falcon. He played in all 16 games just once in his career.
Vick's issue is that he always wants to make the most out of his incredible athleticism, trying to make spectacular plays out of nothing. While that may work once in a while, constantly laying out your body for the sake of one play is not in the Eagles' best long-term interests, especially when you consider the amount of money they are paying him.
Vick only played a handful of snaps in the preseason, as he suffered yet another injury. In response, Vick is utilizing a special vest that is "guaranteed" to protect Vick from harm.
So far, the vest manufacturer is coming through on their promise, as Vick was able to withstand a handful of vicious hits. However, if he keeps taking hits like he did on Sunday, no special vest is going to protect him.
This may be a bit of an extension of the Jets-Patriots rivalry, but these two coaches are developing a rivalry of their own.
Before Ryan took over in New York, the Patriots were decisively the better team year in and year out. Since 2009, however, the difference between the two teams has narrowed.
Both are known as defensive geniuses, but Ryan's defenses have been exponentially better than Belichick's in recent years. Since Ryan took over the Jets, the wins have been about even, the Jets losing four out of seven contests to the Patriots in three years.
It's not a great record, but it's not bad considering the Patriots are a 12-win team—at least—just about every year.
The rivalry took on a life of its own after the Jets were drubbed by the Pats on Monday night in 2010. The Jets responded by knocking the 14-2 Patriots out of the playoffs in the AFC Divisional Playoffs.
The following season, Belichick took great pride in beating Ryan's Jets in the Meadowlands, using some colorful, choice words to describe his team's offensive success.
Neither of these coaches seem to be going anywhere anytime soon. This rivalry could really turn into something special.
There is no doubt that the Steelers have been the better team since the Browns re-entered the NFL, but this once-great rivalry is starting to pick up some steam.
No matter how bad the Browns are, they always seem to give the Steelers a tough game with their underrated defense.
The Browns still have a long way to go before they start winning like the Steelers, but with a new array of offensive weapons, the Browns are not the pushover they used to be.
This divisional rivalry has always been heated, but as the more-talented Chargers keep losing to their once-inferior Broncos, tensions between the two teams continue to mount.
Between a controversial call that cost the Chargers a win in the 2008 opener to getting "Tebowed" at the tail end of last year, the Broncos continue to dash the Chargers' playoff hopes, stealing wins from them every year.
However, the Broncos are not going to be the division's pushover this year. With Peyton Manning calling the shots, the Chargers will most certainly be the underdogs to take the division this year.
It will be interesting to see how this new dynamic changes how these teams play each other, but it certainly makes things more interesting in the West.