From my vantage point, and sticking to the names in circulation, I would rank the candidates as follows (and from the best interest of the campaign, not what I personally want them to do!):
Obama:
Best: Tim Kaine/ Hillary Clinton (my heart says Kaine, but my head says Clinton. Right now, Obama needs a serious shot of adrenaline, and Clinton knows how to fight back)
OK: Joe Biden, Sam Nunn
Poor: Evan Bayh
Awful: Kathleen Sibelius (More communion wars– yeah, that’s what we need…)
Outside the box: Al Gore (want your old job back?)
McCain:
Best: Tim Pawlenty (if you can prize Minnesota away from Obama, you’re in good shape).
OK: Charlie Crist
Poor: Tom Ridge
Awful: Mitt Romney, Rudy Giuliani, Joe Libermann (I would love McCain to pick any of these people which is exactly why he shouldn’t do it!)
Outside the box: Fred Thompson (let’s face it, the VP position is made for him– he wouldn’t need to work that hard!)