% Independent vote for Obama/McCain map:
The Indy vote is a pretty accurate prediction of state results, with only AZ, NE, KS, and NC being "incorrect". NC is surprising in terms of margin, AZ because of home state advantage, and NE and KS due to being strong for the other party. Perhaps western NE/KS are overwhelmingly GOP in terms of registration and all those states' Indy voters live in the more competitive areas.
I made a map of which party's voters had a stronger margin. Keep in mind that some of these are 1% or less.