I think Schaub for sure. His only real knock is injury, but if that happens, plug in Sage who is capable of carrying the team. Look at the options around him (including Owen Daniels and the underrated Kevin Walters!). And the RB game should do better with Alex Gibbs, which I believe helps the QB in the long run.
I think Aaron Rogers is close because they'll be running 4 WR sets (with a lot of talent out there, plus Donald Lee, plus great RB play), but if he fails from the pressure or is hurt (which are very real possibilities), you're screwed. I'd think Rivers after that, especially with his gained experience in the Norv system and the upgrade with Chambers at WR (not to mention the dump offs to LT and Gates).
As for the others, sadly, VY looks like he'll never be a top NFL QB and Hasselbeck will be throwing to less talented WRs for a large part of the year.