I think Kerry is the big loser here.. While his presentation skills were clearly superior to Bush's, I do think he left a lot to be desired in terms of content. The specific details were few and far between. He really needed to give people a reason to vote for him, and he didn't do that tonight. This was a wasted opportunity in that regard. Meanwhile, Bush just needed to avoid the big mistake, which he did, and I think he put Kerry on the defensive a few times.
Kerry also had one statement tonight that could really come back to bite him in the ass, that being his remark that pre-emptive strikes should pass some sort of global test. If Bush chooses to pounce on it (and judging from his response in the debate, I think his campaign will be all over it), it could be catastrophic for Kerry. He and the Dems already has significant problems on the issue of national defense and this statement will certainly be used by the Bush administration to paint him as a far left candidate who will outsource US defense to the UN.