I'll let other people write about the historic and uplifting nature of the Obama victory.
I just want to make a small point on Third Party Candidates. Bob Barr (L) and Ralph Nader (I) were on ballots in several states, and in a few of them, they made the difference in swinging states one way or the other, although not enough to swing the election in either way.
MONTANA (3 electoral vote)
McCain 230,410
Obama 214, 481
Ron Paul 9, 932
Nader 3,499
This was outside the margin of influence, but it's remarkable how close it was. Between Ron Paul and Ralph Nader, McCain could have an additional net 6K votes.
NORTH CAROLINA (15 electoral votes)
Obama 2,101,986
McCain 2,089,826
Barr 25,181
Here it is pretty clear that Bob Barr cost McCain the state.
INDIANA (11 electoral votes)
Obama 1,352,356
McCain 1,329,370
Barr 28,980
Again, pretty clear that Barr cost McCain the state.
MISSOURI (11 electoral votes)
McCain is leading Obama by 5,853 votes.
Nader won 17,767 votes, and Barr won 11,355 votes.
Here, it looks like Nader cost Obama the state.
What's remarkable however, is how many states were won decisively, outside of the margin of influence of 3rd party candidates, ie Florida, Virginia, Iowa, New Mexico, Colorado and Nevada, all states in which Obama won over 50% of the vote.