If Romney wins Michigan, as appears to be happening, the big winner will be Rudy. A loss in Michigan will weaken McCain in South Carolina and Florida, the next two big stops for the GOP. Rudy is still very competitive in Florida, and has banked his whole campaign on a win there. He is campaigning there every day.
If Rudy beats McCain in Florida on January 29, it will revive him for February 5th contests, especially in big coastal states. This race may still have a few turns left if Romney wins tonight.