If Romney loses, I think they'll put Ryan up. He's young, handsome and conservative. I don't think that Christie, who is a bit too NY (even though he's not a New Yorker in the literal sense) and far too moderate, would ever get the nod.
I don't think Hillary will run. Although she and her husband will always be the power couple in party, I think she's done. As for Cuomo, lots of people thought his dad would get the nomination back in the day, and then his career crashed and burned. Who knows?