THERE WAS THE LADY IN THE CATSUIT, BUT WHERE WAS THE DUDE IN A SUIT WITH A BOWLER HAT? The Avengers is pretty much everything you could have hoped for--funny, action-packed, and, yes, even a little tear-inducing. In particular, Whedon nails bringing backstory to characters who were previously underdeveloped (Black Widow and Hawkeye in particular, managing to make Johansson far more than just a sex bomb and Renner far more than just a blank slate) with economy and effectiveness, and defining the relationships between the characters (there is a great romantic comedy banter scene between Downey and Paltrow early in the film, which makes me want to see a Whedon straight romantic comedy).
The one problem I have with the film is the same problem all the Marvel films have had--the villain. In order to be a threat to even one of these superheroes (much less an assemblage of them) the threat must be so ridiculous as to be silly. Some of the precursor films (Captain America, in particular) have done a far better job of it, but others (both Iron Man films, Incredible Hulk) have failed on that note. Vulture annotates who the ultimate villains are (revealed in a post-credits scene that's a blatant set up for Avengers Reassemble), but it's a tricky balancing act. (The Batman movies have done a better job, in large part because Batman doesn't have superhuman powers.)