Hillary would never consent to run as VP, and no candidate would choose her. In the first situation, she spent eight years as a second fiddle with no power in the white house, and would not desire a repeat. In the second situation, Hillary carries too much baggage onto any campaign, including her own, and would not be a good choice. The only reason one might choose her for VP is for her fundraising skills and apparatus, the latter of which will likely transfer to the nominee in any case.
A more likely ticket is Obama-Richardson or Obama-Dodd, presuming Obama gets the nomination. Obama wouldn't want Edwards stealing his limelight, and Edwards' appeal to southern populists is shorted out by Obama's race anyway, so he's out as a VP. The two I mentioned are smart but rather colorless compliments to Obama's charisma, and serve much the same function Gore served for Clinton in '92.