What I'll be watching for tomorrow night

I think we're going to know the winner relatively early on tomorrow, because McCain has so many states in the East that he needs to win. From 538:

Also, there are some states that truly do appear to be "must-wins" for McCain. In each and every one of the 624 victory scenarios that the simulation found for him this afternoon, McCain won Florida, Georgia, Missouri, Indiana and Montana. He also picked up Ohio in 621 out of the 624 simulations, and North Carolina in 622 out of 624. If McCain drops any of those states, it's pretty much over. (Emphasis mine.)

Also, it would seem that McCain must win at least one of the following: Pennsylvania||Virginia.