Rook hits the nail on the head
In terms of a "debate", I'd agree that there was no victory to be claimed.
However, as a re-introduction of the candidates, I think it did help remind us of who these two people are now.
McCain was a great senator, and is probably one of the reasons why he focused on his past reputation so much. But his stances in the debate mostly just highlighted that the things that made him a great senator are the same ones that prevented him from being a successful Republican candidate - and that's all over now. Now he toes the military/oil-backed line. I think he is indeed ready to be President today - pretty much exactly filling the hole Dubya would leave. He would undoubtedly be more articulate, knowledgeable, and likable - but the overall direction of the US would be the same.
Obama is a smart and considered representative of American innovation. Basically, I agree with him that the United States need a change of direction, and I think that he would attempt it with the sort of care and thoughtfulness that would be needed. His method of starting from basic principles and extrapolating to specific actions is very appealing to me, and a desperately welcomed change from message-focused catch-phrases that dumb down everything to a polarized assertion.
It seems clear to me that on of these options is far more advantageous to the United States, both in terms of economic health and moral direction. But, since Americans tend to vote more for personal affiliation than group benefit, it will be interesting to see which candidate better represents the majority of Americans. Are they more like an out-of-date corpse-like puppet, or are they forward-thinking half-breed dreamers?
-- h/t to Rook