I can picture Barack Obama winning the election in two dramatically different ways. One possibility is the landslide. Young people and African Americans turn out in record numbers. The Obama campaign's Get Out the Vote effort is unlike anything in history. As a result, Obama could win all the toss up states, possibly including such improbable places as North Carolina, North Dakota, and Montana. This would be a electoral vote victory in the range of 338-378.
The other road to victory for Obama is the narrow win. The polls would need to tighten, young people would need to disappoint him, and finally, the undecided would need to break heavily for McCain. In this scenario, Obama only wins the states where he is currently polling over 50%. He would fail to win Ohio and Florida, but would still piece together a victory with Iowa, Virginia, and/or the mountain west states. Under this path, Obama is declared president late in the evening with between 272-286 electoral votes.
For John McCain to win, the stars would all need to align. Not only would the polls need to tighten, young people need to stay home, and undecided break heavily for McCain, but a massive wave of infrequent rural white voters also need to turn out in large numbers. Even if all that happens, it would be highly unlikely that John McCain would win a single state John Kerry carried in 2004. McCain could still lose Iowa yet pull off a very narrow between 270-279 electoral victory. If John McCain wins the election it will make for a very, very late election night.