The Republicans are going to try to come up with a very tough, well-known and Tea Party-like candidate.
But the IRs are a bit short on such candidates. So they are looking for newcomers such as MN Congresswoman Michelle Bachman or even former MN Gov. Tim Pawlenty, and a few others. Palin is hoping to get endorsed though I think her chances are slim, partly because she's made it too plainly clear that she's trying hard for it and that might hurt her chances--people just get too tired of her. You'll see other secretive candidates emerge around primary time. They are watching and testing the waters right now.
But victory shall be Obama's again. He's done well, despite our harsh economy.