I'd argue, if you want to track who is most likely to win, then take a look at intrade. They do a remakable job of doing getting pretty accurate results and they did fantastic during the Primaries.
The theory: People don't like to lose their money and make decsions based on how to get more. And there is more going on here than opinion polling. Think of it as the invisible hand.
Today it's Obama 290 to Romney 248. But it can change.
Oh and It was VERY accurate in 2008.
365 to 173