McCain seemed to keep his composure up until Ayers. After that he was just plain hot under the collar. The whole second half of the debate he looked bitter and dismissive. I've criticized Obama in the past for looking arrogant and dismissive; tonight McCain looked more so. If he had any hopes of coming out on top, he needed to be more self-deprecating and let Obama come across as the glib candidate.
Just like the previous debates, McCain failed to look diplomatic and presidential except that he was more animated in this one the the other two. Almost every Obama point from Roe v. Wade to free trade to vouchers he grimaced and ticked. It looked like he was still mad about Ayers and projecting on to every other issue afterwards, and swing voters do not get jazzed about these past issues.
UPDATE: It was fairly clear to me that McCain was making most of his appeals to the social conservative base (e.g., "redistributing wealth," Ayers and "allowing babies to die," all of which fell flat with CNN's focus group of independents) and not to independent voters. If he's still trying to close the deal with a significant portion of his base, can he get the number of independents he needs to win on Nov. 4? I don't see how.