Well the real question is who do they run against any Dem, not just Clinton?  Do they have a deep bench at all?  

If they get the constitution amended, then we may see the Governator run, but he isn't beating an incumbent unless the incumbent is really unpopular... He'd wait until 2016 or take a VP nom with the 2012 person.

So who else... Jeb is an option, but I don't think this country elects a Bush again for at least 30 - 50 years.

Charlie Crist?  Mitch Daniels?  Tim Pawlenty? Mark Sanford?  Rick Perry?