I think that we could well see Kerry having a lead in the polls after that debate. To me, Bush looked strained and nervous throughout, and several times he just seemed to meander off onto another subject. There were at least three questions that he completely failed to answer at all.
A couple of amusing comments that he made included "I send my budget man down to congress" and "[my wife] speaks english a lot better than me".
It could have been a trick of the lighting, but it also looked like Bush had a bit of phlegm in the corner of his mouth for the whole debate.
ops:
I also noticed that he claimed that the US government had stopped the flu vaccine production because it was contaminated. However, I am fairly certain that it was the British authorities that made this call.
Then there was the really fake sounding part during Bush's closing statement when he talked about how had always admired the optimism present in a painting in the White House. That was too obviously written by someone else and didn't sound like Bush talking at all. Something for all public speakers to learn from there.