A caveat: a lot can happen between now and election day (November 6).
That said, I have done the math a few different ways, and if the presidential election goes the way I think it will, this will be fairly close, and hotly contested Ohio will be the deciding state.
Here’s how I think it happens: Obama carries the northeast, pretty much outright, and the west coast. With some of the upper midwest, he gets to 266 electoral votes, just shy of the 270 the winner will need. Romney carries the southeast, some of the midwest, the Plains and mountain states. That gets him to 254 electoral votes.
Ohio has a delegation of 18 electors. Whoever carries Ohio will win; I don’t believe either candidate can win without carrying Ohio.
So, if you want to know who will occupy the Oval Office starting in January 2013, keep your eyes on the Ohio polls.