I thought that the debate was pretty good, although I was disappointed to not really hear anything new from either candidate. Obama definitely got stuck on clearing up the facts, which is a bummer because it gave him less time to talk about new and exciting things, it sorta seemed like him and McCain were bickering a bit. Sadly, he wouldn't have to constantly explain things if McCain wasn't leading such a "uniquely misleading campaign" (media's words, not mine).
I thought in terms of body language, Obama was way better. The town hall format was supposed to favor McCain, who I thought looked awkward, tired, and withdrawn. Obama on the other hand leaned in, interacted with the audience, and seemed very engaged.
One of my problems with McCain and Palin is that they never actually ANSWER the questions. They wax philosophical and metaphorical about defeating evil and supporting the middle class, but without actually saying HOW. Obama (and Biden for that matter) on the other hand always address the question posed to them, usually in a concise, clear, and well-thought out manner.
I think Obama was the clear winner of this debate, although I definitely don't think he made undecideds love him.
Follow this link to read a non-partisan description of each candidates environmental plan and voting record.