A couple weeks back, I was in the "heartland" (rural Midwest - it's where I grew up actually) and it was interesting to get a sense of where people are on the forthcoming elections. Confused, anxious and jaded pretty well sums it up!
IMHO, Obama's ethnicity WILL be a factor. Racism IS alive and well amongst many blue-collar voters, especially in predominately white, rural areas, but also in urban areas that are still racially polarised. In the past, Democrats could count on their votes unquestionably. Not sure about that now. It will be interesting to see. Ongoing bickering between Clinton and Obama I feel has only made Democrats anxious and pissed off.
McCain's an odd choice for the GOP nominee. He has few fans on the far right of the party and amongst fundamentalist Christians, but IMHO, the Republican Party have always been more successful at whipping the "faithful" to vote a straight GOP ticket. Reagan didn't fit the identikit, but they backed him.
Who McCain picks as a running mate is crucial, not just for whether wavering Democrats will hold their noses and vote for him. He's 70 years old and has a history of poor health. If elected, there's every chance the VP will get a turn at the top job. My octegenarian mother is a bit of a conspiracy theorist

but she pointed out that Jeb Bush has been keeping his head down since finishing his 2nd term (you can only serve 2) as Florida Governor in 2006. Hmmmmmmm.