The national popular vote shifted +8% for the Democratic candidate compared to 2004 but some counties voted more Republican. I think we are seeing the most racist regions of the country, running in a belt across the Southern and Appalachian states. This map likely minimizes the extent of the belt, as in southern state counties with large black populations there was a high black turnout and Obama got a higher percent of the black vote.
(image from http://nytimes.com/)
On the other side of the coin is Indiana which swung +21% in Obama’s favor–the biggest surprise of the election this year. It looks like Indiana is finally giving up its claim to be the northern-most Southern state and is rejoining the Midwest.