I agree with whoever said that the opening weekend should be around $45-$55 mill. I'll be surprised if it makes $250 domestic, but I think it will make a lot in the international market, since that kind of action translates easily. Believe me, I want this to do well, because when good comic book movies do well, that means we see more of them. But I think the last one left a pretty bad taste in the average movie-goers' mouths.
Also, you have to remember that Iron Man had a few things going for it. It was the first BIG movie of the season after a long drought. It was a new franchise, not a sequel or reboot. People may have heard of Iron Man, but most knew nothing about his origins. And finally, RDJ. I remember basically every review I read before the movie came out said that RDJ was the reason to see this movie. I haven't heard the same about Ed Norton. I'm sure he's good in this, but unfortunately, all we've heard about is the friction between him and the studio, and we don't even know how much of it is true.
The real question is, if a sequel is given the go-ahead, would Norton even want to come back? I know he's locked into a contract, but if both parties felt that the relationship wouldn't work, I can see them letting him out of it.