The combination of a quick call for Obama in Virginia and the too-close-to-call status on the GOP side has the cable pundits (and me) suspecting that Obama cleaned up among independents--bleeding McCain of a critical base of support in the process.
Virginia may almost be a mirror image of New Hampshire: Independents, assuming McCain had the state in the bag, may have decided to participate in what they (mistakenly) believed would be a closer race on the other side.
--Noam Scheiber