Exit poll results should be taken with a grain of salt, however, demographic polls should not.

[Drunken Irishman]

Those generally give you an idea of who is getting their base out. I never paid attention to the exit poll results leaked by the press. However, it's quite possible the networks leak their demographic polls, like they did in the primary. That will give you an indication of how well each candidate is doing in terms of getting out the vote and winning their core group. If Obama is in the 45ish range in terms of white voters, it'll be a landslide. If he's in the 30s, it could be a long night.

Just keep an eye on the demographic polls. You'll start seeing them around 5 EST, especially for the early states (Indiana and Virginia).