A comment from a MeFi thread:

Factors in the Democrat’s favor this year: a disastrous economy, an unpopular war, an incumbent president with a 30% approval rating, far more money and better organization than the other side, a candidate who is charismatic, smart, accomplished and eloquent, an opponent who is old, out of touch, disliked by a large portion of his own party and a Washington insider when people want change.
Factors in the Republican’s favor this year: the Democratic candidate is black.
Result: the race is dead-even.
No matter who wins, you can learn a lot about America just by looking at where the race stands today.