With the impending nerdgasm of "The Avengers" movie, fans with a solid grasp of history have probably been wondering what the "uh-oh" x-factor was going to end up being. Well, now we apparently may know: HitFix's Drew McWeeny, formerly "Moriarty" of AICN, reports the not-terribly-shocking-news that while The Incredible Hulk WILL turn up in the film, he will likely not be played by Edward Norton again: http://www.hitfix.com/blogs/2008-12-6-motion-captured/posts/exclusive-edward-norton-is-not-the-hulk-in-the-avengers-but-he-d-like-to-be
This will probably be spun as a cost-cutting decision, but it's equally likely that Marvel Studios simply didn't want to work with him again. Norton has a - perhaps overblown - reputation as an actor who insists on insinuating himself into the production side of things; and for good or one thing that's absolutely true about Marvel Films is that they decidedly NOT running things in an "artists' commune" style a'la Pixar. Definitely dissapointing, but for my money "how" bad this news is is heavily reliant on what movie is actually "about" - specifically, what The Hulk is DOING there.
For non-fans: Technically, Hulk was a "founding member" of The Avengers, but for obvious reasons he A.) only stuck around for two issues and B.) entered as a sort-of enemy: In Avengers #1, the heroes (Thor, Iron Man, Giant-Man and Wasp) initially come together to FIGHT Hulk, then he joins the team after it turns out he was being mind-controlled by Thor's evil brother Loki. In Mark Millar's "Ultimates" re-imagining (which had been called an "outline" for an Avengers movie LONG before there was ever going to be one) this was mirrored by having "fight and contain an out-of-control Hulk" be the big initial obstacle for the team.
In other words, there's a certain amount of precedence for Hulk being the "bad guy" (tool of the bad guy?) in the film, which would necessitate that alter-ego Bruce Banner NOT be onscreen all that much (i.e. Hulk gets beaten and morphs back into "some guy playing Banner" at the VERY end.) Obviously, actor-continuity is fun, but speaking for myself if the choice is "Hulk is in the movie but with a new Banner" or "No Hulk," I pick the first one, easily.