Obama / Clinton ticket
I absolutely do not expect this to happen because I feel that a strong and unequivocal message was hammered home when Obama selected Patti Solis Doyle, who was sidelined by the Clintons, as their Chief of Staff for a newly-minted VP candidate. Several commentators also saw this as a "f-u moment". It's also clear that BO prefers to be the center of attention and not to share a stage with any competing force.
Clintonites saw this as the sort of over-the-top, thumb in the eye offense that Obama seemed to relish towards the end of the Primary season and that totally turned off a fairly large segment of her supporters. For this and several other reasons, I also feel that many Hillary voters actually do not want to see this pairing.
I agree with those who think that he will go the safe and boring route.