Is this now the "Best movie you've not yet seen" thread?
Well since I *have* seen the Avengers, I can safely say that it's at least been a couple years since I've seen a movie I've enjoyed so much.
The movie has all the Marvel movie cast in it, most especially Robert Downey Jr., Samuel L. Jackson and Clark Gregg (Agent Coulson) in it, and it was directed by Joss Whedon, who also gave the world Buffy the Vampire Slayer, Doctor Horrible's Sing-Along Blog and Firefly. Just based on that, there was more or less no way I wasn't going to like the movie.
But boy oh boy does it deliver. The enormous green surprise from the whole movie is Mark Ruffalo, who plays play Bruce Banner with a different mix of nebbishness (i.e. less so) and intensity than Edward Norton did. Ruffalo is also the first movie actor to actually perform as the Hulk, using some variation on technology created for Avatar. And the Hulk basically gets all the best moments in the movie. I mean that in the best possible way. If the Hulk is doing stuff, it is a crowning moment of awesomeness, whatever it is. This is a funnybook movie, and Whedon gets that. It's funny. Really funny, both in Whedon's trademark dialogue and in occasional moments of physical humor. It's also brightly colored and upbeat and positive in a way that defies Nolan's Batman films, but without losing focus on the need for genuine (comic book) drama and character-defining moments. This is a movie that kids can go see and they will love it.
Basically every character gets at least one big scene in the spotlight. I was really quite impressed with the way the second act worked, giving the characters the opportunity to engage with one another. If any character got short-shifted, it's probably Thor. On the other hand, the Avengers as a movie draws most heavily on characters and back-story from that film (and least from The Incredible Hulk, if anyone is wondering). The audience does get real justification for why some redheaded chick in a catsuit (Black Widow, who was introduced in Iron Man 2) and a guy with a bow and arrow (Hawkeye, seen but not named in Thor) are doing hanging around with those other guys, something that a lot of internet people were bitching about. I kind of want to say that The Avengers is the "Nick Fury" movie, or the "Captain America" movie, but it's really not. There's just an elegant split between the whole ensemble.
Plot? In the opening moments of the film, Loki steals the Tesseract (Cosmic Cube, for those in the know) that was last seen being retrieved from the ocean depths at the end of Captain America. Loki has enlisted the aid of a race of alien invaders in a plot to use the cube to allow them to come and conquer Earth, which he wants to do in the name of his ongoing rivalry with Thor. The first act then introduces the various characters, followed by 40 minutes of the characters coming together in various sorts of conflict (it's a Marvel trademark that its heroes fight when they meet each other: Here we get Iron Man and Thor, settled by Captain America; Black Widow and the Hulk, settled by Thor; Black Widow and Hawkeye, settled by a steel rail). The second act flows seamlessly into the last 50 minutes of the movie, which essentially a non-stop action sequence. I kind of want to describe individual moments that are the cinematic equivalent to comic book full-page single panels. I shouldn't. I can't. But they're there.
It should be noted that the version of the movie I saw has TWO stingers, one after the short, animated credits sequence and a second one at the very end of the movie. The second stinger was filmed by the cast as a last-minute addition the the movie and as I understand it, it wasn't included in copies of the movie that were released in Europe ahead of the US premier.
Marvel Studios exists entirely to continue this franchise. Its movies, just like the comics, share a world that will continue into the indefinite future. I'm sure we're going to get a Hawkeye or Hawkeye/Black Widow movie. There's been talk of doing Ant-Man, Black Panther, Runaways or Doctor Strange. My friend was concerned that there would be a sequel. There will be a sequel. There will be more Thor, more Captain America, more Hulk and more Iron Man. More characters will be introduced and there will be two or three Marvel Studios movies per year until 2016 or so. But the Avengers was the concept that has been building since Iron Man, and it worked better than I ever could have imagined.
If you suddenly become interested in the comics, the thing to say is that it would be nearly impossible for a new reader to go to a shop and pick up current Marvel Comics titles with any chance of having a comprehensible experience. Don't do that. You will not know what the hell is going on. The Avengers movie is a complicated mish-mash of creator vision that does not easily translate from the comics. Furthermore, Marvel's publishing arm has a really weird policy on printing and re-printing collections of issues, which means that it can be very difficult to track down the best stories to recommend to new readers. However, if you really want to read something, the first two volumes of "The Ultimates" by Mark Millar are probably the closest to the movie universe, and the story there is self contained. Just don't read any of the other "Ultimates" comics because they are god-awful. I'd also suggest Ed Brubaker's Captain America, particularly the omnibus collection containin issues #1 - #25. Iron Man and the Hulk are both VERY hard to get a handle on, but the omnibus collection of Matt Fraction's Iron Man can currently be had on Amazon for $16 and is probably closest to the movie version of Tony Stark. J. Michael Straczinsky's run on Thor does not have an omnibus collection, but there is a shorter trade paperback containing at least one recent character arc. Finally, Loki is currently starring in a series of his own called Journey Into Mystery. It's not the same Loki (it's complicated), but the series is largely self-contained and it is massively entertaining. If you really, REALLY want to pick up individual comic issues, Marvel titles with a .1 (point one) numbering are either self-contained, more self-evident or the start of a new character arc.