It's all been leading up to this...
So I'm not going to lie. The Avengers totally rocked my socks off. If you haven't seen it yet, stop reading and go see it (after you've seen "Iron Man", "Iron Man 2", "Thor", "Captain America", and maybe one of the "Hulk" movies although that's not as important) because SPOILERS!
It really does a fantastic job of tying all those other movies together. All the returning cast gives it their all in performances and it felt like a true crossover.
The biggest pleasure for me was seeing Mark Ruffalo as Bruce Banner. Now, I enjoyed the Ang Lee/Eric Bana Hulk from 2003 for what it was. The 2008 Edward Nortan "The Incredible Hulk" somewhat less so, but Tim Roth saved it for me. Mark Ruffalo does the best job I've seen with the character. He's the first one that really gets it to me, and it was so wonderful seeing him bounce off the veterans (or, in the case of Tom Hiddleston's Loki, bounce the veterans off things)
Now, I very rarely read issue-to-issue comics. They tend to be too soap-opera-ish for my taste. So I was a bit confused what the alien race was and who the guy in the stinger was ("Thanos" I read?). I was just disappointed that it wasn't Red Skull, because I don't buy his "death" for an instant and its one of the few Hugo Weaving roles that doesn't sound like Hugo Weaving and I'd like more please.
I was also shocked by Coulson's death, until I remembered who wrote and directed this movie and that he's apparently into that sort of thing (I don't really follow Wheadon; I'm one of the few that prefer Movie!Buffy to Show!Buffy by a country mile. I just know he killed off Steve the Pirate for no good reason).
But that's my only real complaint. Black Widow and Hawkeye were well-rounded for being relatively normal humans. Random Harry Dean Stanton was pretty cool, but random. There are so many great moments I can't list them all. If you're a fan of superheroes, you need to see this film.