Without seeing or hearing anyone else's analysis, I'd say McCain was the best I have ever seen him. Whether or not that will be enough to swing things back his way is harder to say. McCain hit Obama repeatedly, and, IMHO, effectively. He successfully brought up many topics that Obama would have preferred to avoid: Joe the Plumber (new celebrity!); abortion and opposition to the Born Alive Act.
I wish he would have responded better to Obama (yet again) claiming that he's giving a tax cut to "95%" of the people. I also wish he would have done a better job at defending his health care plan, which is much better than Obama's. Obama parried the Ayers issue fairly well as far as people who aren't paying attention will know.