Obama '12 seems likely to me: both parties will be extensively internally hollowed out by this point.
The bigger impact will be in the change in policies from President to President, not that we'd have multiple one term Presidencies in a row which is fairly common. From 1953 to 1989 only two Presidents - Ike and Reagan - were elected to two full terms. In fact, having every President from 1993 to 2017 be re-relected is what's unusual.
2016 is likelier. Obama's second senate term would be ending, and there would be a widespread assumption that McCaain could be reelected, especially if the recession is not delayed.Obama '12 seems likely to me: both parties will be extensively internally hollowed out by this point.