I saw The Avengers. And all I've got to say is "damn!" It was quite possibly the best action movie ever captured on camera. Loved the characters, loved their chemistry, and loved the humor. The only problem I had was the villain Loki -- Tom Hiddleston plays the part well, but I never really thought the character was all that menacing, and his costume made him all the more laughable.
Mark Ruffalo's incarnation of Bruce Banner and the Hulk is, by far, the best, in terms of character and the CGI. Here, the Hulk looks incredibly realistic. And since Mark Ruffalo did performance capture for his green alter ego, you get more of the same core mannerisms of both Banner and the Hulk. And unlike Ang Lee's Hulk, which took itself seriously (despite amazing CGI for the title character at the time -- the close-up shots are still impressive), and unlike Edward Norton's overall forgettable incarnation, The Avengers' Hulk is given a dose of humor, and obviously, the film itself has nearly just as much comedy as action (often thanks to Robert Downey Jr's smart-assed Tony Stark/Iron Man).
And it was rather interesting to see Cleveland's Public Square transformed into Stuttgart, and the Terminal Tower transformed into some random building therein.
EDIT: That's my other complaint -- STOP USING HANDHELD CAMERAS!!! It doesn't make a movie look more realistic, it just makes it look more amateurish.