Here is the list from the Washington Post, both parties:

MOST LOGICAL VEEP CHOICES?

Here is the Post's list of the "five most logical veeps," assuming McCain and Obama are the candidates, ranked in the order of the likelihood of being chosen.
REPUBLICANS

5. Former Gov. Mitt Romney of Massachusetts

4. Gov. Charlie Crist of Florida

3. Former Rep. Rob Portman of Ohio

2. Sen. John Thune of South Dakota

1. Gov. Tim Pawlenty of Minnesota

DEMOCRATS

5. Former Sen. Sam Nunn of Georgia

4. Gov. Tim Kaine of Virgina

3. Sen. Hillary Rodham Clinton of New York

2. Gov. Ted Strickland of Ohio

1. Gov. Kathleen Sebelius of Kansas