John Edwards: His plans on health care and global warming moved the entire race to the left, and he had an astonishing number of good proposals on everything from making sure poor people could get fresh produce to regulating hog waste. I don't think that anybody available would use the VP media spotlight as well as Edwards would. And after two and a half years of repenting his war vote and rejecting the 'War on Terror' framework, he's a fine partner for Obama on foreign policy issues.
Not only will he (and Elizabeth!) push hard for universal health care within the Obama administration, but he's about the best weapon you can imagine to sell the plan. If Judd Gregg or George Voinovich are filibustering health care reform in 2010, Obama could send Edwards to NH or OH and have him spend a week telling stories about little girls who died because they didn't have health care coverage. That's what he used to do for a living, and he did it pretty darned well.
As far as electability goes, take a look at the recent OH and VA polls that included VP candidates. Sure, Edwards' advantages over the other Democrats are mostly name recognition. But I didn't expect any VP possibility to move the numbers this strongly. When you add on Edwards as a VP, he adds between 3 and 9 points to Obama's total in Ohio, depending on who McCain is paired with. He adds between 2 and 11 points to Obama's numbers in Virginia. None of the other Democrats added anything to Obama's numbers (no strike against them, because nobody knew who they were). I look at this as a favorability test, and it's one that Edwards passes. Furthermore, McCain has a pretty terrible anti-worker voting record, and the mill worker's son is exactly the guy who could drive that home.
Kathleen Sebelius: Her story in Kansas is a barrel of awesome. She's a popular pro-choice Governor who fought with unprecedented success against health insurance companies (from whom she refused to take contributions). The best thing -- and the part that fits best with the Obama message of national unity -- is her uncanny ability to turn high-profile Kansas Republicans into Democrats. The former GOP state party chair? Now her lieutenant governor. The formerly Republican Attorney General? Turned into a Democrat. Six GOP members of the state legislature became Democrats under her watch. Of course, part of that is because the Kansas Republican Party came apart over teaching evolution in the schools. But she was there to pick up the pieces and take them home with her.