I'm in total accord with John.
There is no, nudge-nudge coming for Sam Nunn... Some things you simply do not recover from.
I'm very partial to Richardson in the Veepstakes, if only he were better with the media and crafting soundbites. As a VP he's great from so many perspectives: he's got the high-level envoy stuff down (which can be very valuable in a crisis situation); he seems to like the ceremonial stuff (as little as I can tell); he's not pushy; and he comes with exceptional experience in the Congress and as a Governor ... He's Hispanic, he's from the Southwest (in play), he's a progressive Catholic not too much from Massachusetts, and he's written a book about energy policy.
Update: AS finds Steve Clemons with a somewhat more politic take on the matter.