(Here's my reasoning. As of 24-25 October, ABC's electoral map gives Obama 311 votes to McCain's 163, with 64 being too close to call. I believe the states that are labelled 'moderate Republican', 'marginal Republican' or 'too close to call' will gradually be won over by Obama before election day, so I've counted only the electoral votes of strongly Republican or very strongly Republican states in favour of McCain. That only yields a total of 134 votes for McCain, leaving 404 for Obama. See map and table below.)
And why do I think the moderate Republican states will ultimately swing to Obama? Many reasons - Colin Powell's endorsement, Sarah Palin's un-hockey mom wardrobe that should speak louder than her pro-American rhetoric to undecided voters, the lingering fears of an economic collapse and a recession that alienate voters further from the Republicans whose cronies and appointees are perceived as having caused the whole mess, attacks on President Bush by McCain and Palin (!) that may put some Republican voters off voting altogether, my expectations of a high voter turnout that's usually a good sign for the Democrats, and my belief that there is a 'reverse Bradley effect' at work that prevents many people in conservative neighbourhoods from openly backing Obama in opinion polls, understating his actual support.
We've seen a generation of "Reagan Democrats". Welcome to the Obama Republicans. I believe they're called Obamicans.