What Obama has going for him in winning a second term is the widespread perception that the economy is in an unprecedented crisis, and the natural fluctuations of the economic cycle. Whatever Obama does for good or for bad, it’s highly unlikely that the economy will be worse in four years then it is now. Obama will say “yes we still have our work cut out for us, but look how far we’ve come under my administration - just give us four more years so we can continue to build on the progress we’ve already made”, and it will make sense to a lot of people.
If I was setting odds, I would say he’s about 80% likely to win in 2012, at this point.