I think Obama would win easily barring a major gaffe or some sort of scandal, which hopefully would prevent Obama from winning the nomination. It's not all about ideology or experience, and most voters, I suspect, would connect better with Obama. I'm not going to do a map, but I think it might surprise a lot of you.
Also, I hate the idea of Obama as veep. He adds no experience to the ticket and his vision/charisma is deflated by being the second fiddle (see Edwards in 2004). If Obama fails to win the nomination, he should not accept a veep slot, but build up his resume in other ways (in the Senate, or possibly by cleaning up Illinois State Gov't in the governor's mansion).
What has Obama done compared to McCain that would make him a strong national security President?