Kerry would not beat Jeb in 2008 because Jeb wouldn't run.
In 2012, Jeb will defeat all comers including a Hillary re-election.
In 2008, the best bet is Frist. Give him a shot...he could be another GREAT president. Many don't know it, but he's got an 89% ACU rating as a conservative.
And rising, since he became majority leader, its risen to 89, it'll be in the 90's in a year or so.
Won't go much higher, since he's leaving the senate in 2006.