As it often is, the term, 'All Time,' is a but misleading here. Superman and Batman made it to the silver screen before the 2000's, but just about every other property had to wait, which means that unless you're picking one of those movies, or their sequels, your test sample is pretty damn small. Like, 2000-2012 small. Despite that tiny window, there have been a variety of winners already, from the first and second X-Men, to Marvel's wheelhouse, and so forth. The Avengers has immediately joined the all-time club, and deservedly so. It's slick, fun, and full of both great characters, and gonzo action sequences. I personally have a few issues with it, but this article isn't so much about bashing Marvel's massive tent-pole as it is returning the crown to its rightful owner... or splitting it between its rightful owners, as it were.
The first, and most obvious challenger is The Dark Knight, a movie that essentially assumed the mantle of Best Superhero Movie Ever upon its release in the summer of 2008. Epic, propulsive, and possessing Heath Ledger's legendary performance, Knight saw superhero flicks to a new realm, one wherein audiences were expected to juggle about 15 balls at once for two and a half straight hours. Gone was the levity that the genre was used to, replaced with sorrow, loss, and bravery under fire that would have made the Bard proud. The Joker was such a dynamic villain, attacking Gotham with twisted mind-games, prompting Bruce Wayne to partake in some patriot-act style invasions of privacy. It's a meaty story, brilliantly shot, and stitched together in such a way that glues eyes to screens. Simply put, The Avengers weighs about half as much as Batman's last outing: The plots of its villain boil down to simple, 'I'll take over the world!' cliches, the visuals are no where near as entrancing, and the actual feeling that something might go wrong for our heros is no where to be found. But The Avengers never wanted to be The Dark Knight, you say? It's goofier, more true to the way that comic books actually read, and simply more fun, you say?
If that's the game that you want to play, then Spider-Man 2, for my money, takes the cake. Director Sam Raimi has a masterful way of making fun of what's onscreen without stripping the audience of anything to care about. Spider-Man was a winner in pretty much every regard, and then its sequel took all of that, and made it even better. Though Joss Whedon works wonders with his massive cast, the silly, endearing, empathy-exuding performance of Tobey Maguire connects on a much more emotional level, all while being wholly true to the wizz-bang nature of comic books. Yet again, Alfred Molina's Doc Oc is a much, much more compelling baddie than Tom Hiddleston, not necessarily because of the respective performers, but because Octopus actually has a back story, and ethos attached (Not to mention a few terrifying appendages). You could argue that Loki was already developed from Thor, but that doesn't really excuse the fact that, in the duration of the specific movie in question, he mostly just sneers, and stand idly by as a hoard of CGI goons do his bidding.
So, there you have it. I'm not really sure which one out of Spider-Man 2 and The Dark Knight I personally would have sitting on the throne; It kind of depends on the day. Serious-minded, sprawling, thought-provoking: You're going Batman. Ah-shucks, gee-wizz, popcorn-munching glory? It's the web-slinger. Sure, The Avengers kind of straddles the line between those two polarities, but when said polarities are as perfectly realized as these two, picking an in-betweener is hard to justify. You can slot The Avengers as high as second, but in the opinion of this writer, Iron Man and friends have no business claiming the #1 spot.