Kerry won the debate last time because Bush was weak beyond belief. Whereas Edwards attacked like hell tonight, his opponent showed very little weakness. If Cheney were knocked down in this debate, then we would be closer to a regime change in November. Bush owes Cheney a keg of beer (at least), because this old frat brother did not embarrass him.
A side note: some people were worried that Edwards might exhibit some lightweight "TV Weatherman" moments, just because he's got the looks, but, no, Edwards is no weatherman, he is the anchor.