I personally see Thor making 160-180 domestic, and 230-250 foreign. It's going to be tight on a sequel...studios only net about 55% of the gross, plus you have to figure that after Paramount's cut, and the Marketing costs, that Thor will barely be making a profit.
I'm still a little shakey about Paramount's role, and what financial responsibility it assumes as distributor, but we're looking at a 150 million dollar film, with at least 50 million dollars in marketing budget. After the theater dips it's beak in my predicted 410 million dollar worldwide gross, it'll be down to 225 million. Paramount takes 10% for distribution, taking us down to 203.5 million...
If marvel spent 50 million marketing this movie they'd be down to making 3.5 million dollar profit on this movie. If they spent more than that, then they'll still be in the Red on the 400+ million gross. That'll of course be fixed when the movie hits dvd and blu ray, but still, there's plenty to worry about with Thor, and plenty of possibility of it not getting a sequel.