I think it will be a governor, on the younger side - all of Crist, Pawlenty and Sanford fit the bill. If I had to pick one, I’d say Crist is the most likely, because he should lock down FL.
This George Will article is interesting:
http://www.washingtonpost.com/wp-dyn/content/article/2008/02/22/AR2008022202173.html
ADDENDUM:
Another interesting piece:
[i]Handicapping the VP Race
By DAVID ROTHSCHILD and JUSTIN WOLFERS
February 12, 2008
With the race for the Democratic presidential nominee likely to stretch on for some time and the contest for the Republican ticket basically over, let’s look at something fresh: Who will be the Vice Presidential nominees?
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With Mr. McCain all but locking up the Republican nomination, forecasting the Republican ticket seems more straightforward. Mr. McCain’s advanced age means that he must look beyond pure electability, as succession concerns are likely to be important.
While Mike Huckabee’s recent strong performances have done little to increase his chances of winning the Republican presidential nomination (he is currently less than a one-in-30 chance to beat Mr. McCain), he is now a one-in-four chance to be his VP nominee.
Mitt Romney traded as high as 18% right after dropping out, but has quickly fallen to about 8%. The other likely contender, Governor Tim Pawlenty of Minnesota, is largely unknown outside the Midwest. But as co-chair of Mr. McCain’s campaign, he is rated a 16% chance. Rudy Giuliani’s stock has largely faded in the last week, while Secretary of State Condoleeza Rice, who would certainly add interesting demographic balance to the ticket, is about a 5% chance.
But the real favorite to get Mr. McCain’s nod is that elusive “other” candidate, currently rated about a one-in-three chance. That field definitely includes the former Democratic vice-presidential nominee, Senator Lieberman of Connecticut, who was recently stripped of his Democratic superdelegate status for endorsing Mr. McCain.
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David Rothschild and Justin Wolfers are PhD student and assistant professor, respectively, in Business and Public Policy at the University of Pennsylvania’s Wharton School.[/i]