I think that the way Hulk was handled in the Ultimate Avengers animated movie is how they should use him in the live action version. Watch it. It's good. He starts off as a "bad guy" of sorts (everyone knows he's not evil, he's just misunderstood... & you know, Hulk kinda has a bit of a temper). Anyway, he basically has his way with the Avengers... Seriously, WATCH IT! Tell me you wouldn't want to see Hulk kicking the living crap out of Giant Man on the big screen!!! & Iron Man!!! & Cap!!! & Thor!!! He beats them all down... with authority... & I must say, as a Hulk fan, it was freakin' awesome!!!
Then, the Avengers NEED Hulk to help them stop a major threat to human life/civilization on earth & so we get both Hulk the "villian" AND Hulk the "hero" all in one amazing movie...
MARVEL, listen up! Have a meeting & watch the Ultimate Avengers animated movie you put out. It was pretty good. Take that base story, change a few things around to make it more pleasing to the average moviegoer & POOF! Money in the bank.
PS: MARVEL, You should hire me to make these kinds of decisions for your films. I will never fail. Trust me. Here's proof... I predict that if you persist with making Thor, it will not do very well. If it were my decision, I'd hold off on it until AFTER the Avengers.
While I'm giving you free advice, have this... To build more anticipation for your films, I'd minimize the releases for the next couple years... Do this... Captain America in 2009 (& it better be set in WWII or it's gonna flop), Avengers in 2010... Get crackin'