This looks like a good option for a poll. Here are my candidates off the top of my head, in order.
1) Tarvaris Jackson. He's really the only guy I see getting pulled soon. He's easily the worst starting QB in the NFL right now.
2) McCown. I don't know enough about him to say if he's any good, but he looks like a place holder for Gabbert at this point. Iffy team means quick hook to the kid.
3) Grossman. One good week isn't enough to erase all the doubts and I think WAS has a legit shot (albeit outside) at the playoffs. If Shanny feels QB play is holding them back, I have no doubt that he'll roll with Beck.
4) McNabb/Hasselbeck. I wouldn't be surprised if neither gets pulled all season as I think both were brought in to start the entire year, but I also wouldn't be surprised to see the rooks get a chance once their teams fall out of the playoffs.
5) Campbell. OAK has enough weapons on offense and Campbell just isn't good enough. Not that the bench with Boeller and Pryor is much better at this point, but with OAK, anything is possible, even a Garrard signing.
6) Alex Smtih. I actually strongly doubt that he will get replaced and if he does, it won't Kaepernick, who is a long way from being ready. It will be Garrard.