Here is a chart I have made with statewide vote totals for most partisan elections. I have been doing this to see what the swing was toward the Republicans and loss by the Democrats. It appears at this time that the average in 2008 was 52% Dem 46% Rep, and in 2006 it was 51% Dem and 45% Rep. workin on 2004. So I think there was a considerable swing away from Democrats in 2010, probably 6 points.
I also have a page that has links to every states website information.
http://www.scribd.com/doc/44304962/2010-Average-Vote-by-State
