Obama and McCain are both fucking horrible. It's a matter of picking the lesser of the two evils. Obama only talks about "change", but his "change" is an even more centralized government, which isn't "change" at all. McCain's campaign is focused around the same ideas. As Hitler wrote in a few of his books or diaries or whatever; War = a more centralized government.
It doesn't matter who wins, I see it as 4 more years of the same. Though if Obama wins, the mainstream media might look at him in a much better light than Bush and give the illusion that his "change" is awesome, but it's just an illusion. Exactly like the illusion that we have two different candidates to choose from.