Perhaps the most sensible place to start, then, is to examine those who played the key roles for the Gunners. They include those who contributed to an early 4-0 deficit and also those who inspired the eventual 7-5 turnaround.
Arsenal's heroes and villains are headlined by Theo Walcott, who showed what he can do when motivated, and blunder defender Laurent Koscielny, who continues to be plagued by errors.
Here are the key figures from Arsenal's remarkable and thrilling Cup comeback, beginning with the villains.
Young Argentine Damian Martinez might already be consigned to the long list of indecisive and mistake-prone goalkeepers recruited by Arsene Wenger, after a calamitous performance.
The 20-year-old was clearly nervy from the start, but simple jitters do not excuse his many follies at the Madejski Stadium. Martinez hesitated when coming for crosses and his overall judgement left a lot to be desired.
Without doubt, his biggest error was the one that gifted Reading their third goal. While Arsenal's comeback was the stuff that dreams are made of, the sight of Martinez slapping Mikele Leigertwood's shot into his own net, was the stuff of classic comedy, or should that be tragedy?
He may not have received much help from a ponderous and leaden-footed defense, but Martinez certainly played his part in Arsenal conceding four first-half goals.
Spanish central defender Ignasi Miquel certainly makes a shaky makeshift left-back. Despite having played in the position before for Arsenal, Miquel constantly failed to track runners down his flank.
That left Arsenal exposed to dangerous crosses and Reading's second and fourth goals were the inevitable result. Miquel just couldn't adjust to the pace of the game in wide areas.
It was a shame to see Miquel struggle as badly as he did. He remains a promising prospect and eventually his fatigue saw him to succumb to a late injury, after once again being harried near his own box.
Martinez and Miquel's youth could excuse some of their mistakes, but Laurent Koscielny certainly should know better. The France international suffered through one gaffe after another in the first half and looks a shadow of the assured and steady player he was for parts of last season.
Koscielny made bruising veteran Reading striker Jason Roberts look as though he ought to be playing for Barcelona or Real Madrid. Roberts baffled Koscielny to open the scoring with some deft, but simple movement.
He also bullied the Frenchman all night, easily overpowering him in every one-on-one duel. At one point, Roberts turned Koscielny with embarrassing ease and the clumsy defender's oafish attempts to bring him down were equally cringe-worthy.
Koscielny's desperate and wild first-half lunge that culminated in another own goal, summed up most of his night. Only scoring Arsenal's third goal late on, added some gloss to a forgettable evening for the ex-Lorient stalwart.
Heading into the game, much of the attention surrounding a young German Arsenal star was focused on Serge Gnabry. However, it was fellow German starlet Thomas Eisfeld who looked the more impressive.
Entering the game as a second half substitute along with Olivier Giroud, Eisfeld immediately improved the quality and flow of Arsenal's passing play. The former Borussia Dortmund prospect held his position well and showcased a varied delivery and sure touch when distributing the ball.
This was a promising cameo from Eisfeld, who was technically confident and and showed the creative willingness that is essential in Arsenal's style of play.
Olivier Giroud powered in Arsenal's vital second goal, giving the team genuine belief that a sensational comeback was possible. The French striker also made a big difference to Arsenal's attacking play, carrying the fight to Reading with an encouraging mix of mobility and strength.
He didn't always win aerial battles, particularly with his back to goal, but Giroud was a constant threat in the box. His movement was deft and varied and regularly split the Reading back line apart.
The goal is vital for Giroud ahead of a run of big games where he may be required to lead the line. He showed enough here to indicate Arsenal fans don't have to worry too much about that prospect.
Marouane Chamakh toiled hard without much quality to show for his efforts, for much of the game. However, the Moroccan striker rates a place among Arsenal's heroes for his two well-taken goals in extra time.
Chamakh produced a pair of classy finishes that reminded everyone what he is capable of and made you wonder what exactly has happened to that player who began his Gunners tenure in prolific form. Chamakh's first strike was produced thanks to the decisive action Arsenal fans have rarely seen from the often timid former Bordeaux attacker.
His quick and sweeping shot gave Arsenal their first lead at the eye-popping score of 5-4. After Walcott cancelled out a fifth Reading goal, Chamakh latched onto a long clearance and calmly lobbed the ball into the net to finally seal the game.
It was pleasing see a periphery figure emerge from the doldrums in such style. Wenger will hope Chamakh can use the showing to rescue his Arsenal career and still play a vital role in the squad.
Theo Walcott might just have made a believer out of one of his harshest critics. Regular Bleacher Report readers will know that this author has been critical of Walcott in the past.
The contention has never concerned Walcott's talent, but rather his effort and the notion that he has to play centrally to be effective. However, after watching Walcott wreak havoc in the Reading defense with a series of central runs in and around the box, it might be time to grant the contract rebel's wish to start through the middle.
Walcott regularly glided in from wide areas and quickly darted through gaps in the middle. The speed and craft of his movement frightened every Reading defender and created huge spaces for other Arsenal attackers.
This is the kind of movement that should be a regular feature of Walcott's game and not just a fleeting glimpse of what might be. He was rewarded for his efforts with three goals, showcasing not only his pace, but also his intelligence in the box.
Based on this performance, Wenger needs to experiment with ways to involve Walcott more through the middle. The England youngster has certainly earned the right to have a start as a central striker.
The Capital One Cup quarterfinal, a tie Walcott's dominant, match-winning performance guaranteed, is the ideal time to begin those experiments in earnest.