Obama can't pick Biden because he looks like a crook, and at the same time looks like he should be on the top of the ticket instead of Obama.
He can't be Sebelius, because any woman except Hillary would send Democrat women into a frenzy, plus she gave the response to the state of the Union that could have been given by a skeleton robot.
He shouldn't pick a General or Sam Nunn because the overwhelming compensation for his lack of experience will shine through.
He can pick Kaine, but it would be a big mistake because it would in a no experience ticket.
Bayh or Jack Reed seem most logical. Both have experience but don't come off as Washington insiders. Though I don't think Reed offers and electoral help, while Bayh could get Clinton's people on board, which could translate into Clinton voters for Obama.
Hillary? At this point, why not?
Darkhorse pick that would make a lot of sense. Senator Ken Salazaar from Colorado. Why? He is from a swing state that Obama needs, plus Salazaar won there in 2004 not the best Democrat year. He is Hispanic which could instantly increase Obama's Hispanic support. His brother is a Congressman from another Colorado district to help win CO. And finally he has been in the Senate for since 2004 so while he doesn't have an abundance of experience he is not a newcomer, and he was Attorney General for 6 years of Colorado. Experience without D.C. He won't pick him most likely but all and all and interesting choice.
Finally, its probably going to be Bayh