I would definately go with Obama here, but I must say that there are a lot better Republican choices out there. Romney has flipped on almost every political issue he has been involved with, one day he is a govenor supporting the very liberal policies and governent involvement of healthcare in his state, then the next day he is a presidential candidate putting his crazily conservative, Mormon ideas on the rest of us.
If Republicans put forth a reasonable, moderate candidate, such as Olympia Snowe, I dont think Obama has a chance in 2012. Not only would Olympia Snowe win with her policies in today's political climate, but the black man vs white woman racial tensions would come into play here in Snowe's favor (its sad to say but we all know that this would be factor).
Although I would like to warn Republicans that 2012 may not be bright as they think. Americans are easily presuaded by our country's economy, and if Obama is in office when the economy turns around he will be in a great position for re-election. Let me remind you that Franklin Roosevelt and Ronald Reagan faced unpopularity and difficulty in their early years, but once the economy turned around (regardless if you think they are responsible for it or not), they became super popular with the American people and invincible at the polls.