I was hoping for a fun movie that didn't violate the story lines and tone of the other Marvel movies i.e. Iron Man, Thor, Captain America and The Hulk. I think the Hulk's story and the tone of his character was much different than the Edward Norton character, but given the tone of The Avengers of building a team to save the world....well, it just worked for me. Everyone else stayed very true to the character they played in the stand along pics. I was also hoping that each character would get the right amount of screen time to make if feel like a true "team."
I thought Joss Whedon did a fantastic job at all of this...creating a team, staying true to the stand alones, creating an amazing new synergy between the characters...it was great.
Aside from all of that, it was just a great action movie. Fun and easy to watch. Outstanding!