suike, my friend :P,
true ...polls can vary in a week's time. if you remember, El Gore was a whopping 10 points ahead of Bush one month before the election in 2000 only to lose to him a month later. However, at this stage, Obama is going great guns with offensive campaigning at red states. He is not even too much worried about the swing states at this stage. That's what I would like to call - confidence (a move towards a landslide win, if you will ).  Unless he comes up with something extraordinary at today's debate or  in the next few days, it's going to be a really really tough job for McCain to come out of this lag(pulling off a victory is a far cry for him). The way I see this, it's slipping away from him by the day as the big day is approaching...

Kishnekale bro,
I don't claim either that the Krugman's win would have a drammatic increase in the vote count for Obama. What it would do , IMO, is that it would boost the morale of Bush haters(especially his policies on tax cuts and economy in general) and with Obama campaign's main tactics in this campaign being making McCain's prospective presidency look nothing more than the Bush's last 8 years; the Krugman's win will startle the nervers of the McCain supporting centrists and swing voters in the coming few days.

Here's a more than 2 year old video of Krugman where he sorta predicts housing bubble burst and recession in the near future.