"Never cook with a wine you won't drink."
Obama could win it in a landslide, and these jokers would still claim it was just dumb beginner's luck:
A Democrat was always likely to win the 2008 presidential race. I'm not saying that will definitely happen in three weeks, but if it does, that will simply confirm longstanding political patterns and reflect how and why swing voters swing. The Obama and McCain campaigns will have affected the outcome somewhat, but unless it's a blowout, their contributions will not have mattered much (sorry, political consultants, but some of us see right through you).
The Bush administration has been fraught with errors of its own making and crises not of its own making. The president is unpopular. The people are upset. Generally speaking, then, the natural outcome is a change of party. That Obama isn't running away with this by a huge margin is testament to the fact that the electorate remains essentially Center-Right, not Center-Left. Why do you think Obama is running as a anti-corruption, war-fighting (in the Stans), tax-cutting deficit hawk with nary a thing to say about cultural issus?
Realistically, I think Osama bin Ladin himself could break into the National Archives and take a dump on the Declaration of Independence and Obama would still win handily, and it's got jack shit to do with the economy. It's got everything to do with believing it's a good idea to have someone with steady nerves in charge of the ship while we're sailing through a mess of icebergs.