Got this [7:13] via James Fallows who had the misfortune to cover all the Democratic primary debates -- and who then ran away to continue living in China and covering our future global peer nation rather interestingly. The video gives an interesting sense of why Obama might have chosen Biden.
If some of your criteria in a new Administration are articulateness and brains, the guy certainly qualifies. There's no suggestion that he stands for anything but smarter empire, but then there's no suggestion that Obama does either. Biden was wrong on the Iraq war vote and now knows it.
Interestingly, Biden has the lowest net worth of any Senator -- so he must not be conventionally corrupt, either, since he's certainly had time in office to make out like a bandit.