538 has run 10,000 simulations of possible outcomes for tomorrow, of which McCain won 624 times. Link
...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.