Granted, Romney came across a lot stronger than I'd expected, and Obama's body language needs some work. He acted like he was off-camera when Romney was speaking, and he didn't make much eye contact with the cameras. But Obama didn't lose, and this isn't over.
The main factor in play is going to be the post-evaluation. Romney threw out some red meat for his followers, but also a lot for the fact checkers and the Obama campaign to chew on over the next few days. Obama didn't get many hard hits in, but he doesn't have to. Romney was all over the place, made a lot of claims and commitments that he's going to have to answer to tomorrow.