I can't envision them doing Thor. I mean, it's possible, but to me, even after Thor 3, Thor isn't "loved" in the way that Spider-man or Iron Man or the Hulk are loved. I think it'll be Hulk. I know he hasn't had his own movie recently, but he's got the most cachet (not a misspelling) of all the options. That or they could do Spider-man again I guess. Or comic book Avengers. I'd say I'm 65% sure it'll be Hulk, assuming the rumor is accurate.