Professor Opliphint shares some thoughts on the debate at Westminster. He makes a pretty good point about the medium impacting the message (the debate was being filmed for a documentary) and he notes the moment in the debate when it got real:

DW: I have faith in the Bible, you have faith in reason.
CH: No, I don’t have faith in reason; I’m inclined to doubt something if its truth will be something that suits me. We [i.e., atheists] don’t love the idea that we will be annihilated; we don’t indulge in wish-thinking. We don’t assume what we’re asked to prove.
CH: You’re a man of one book
DW: You’re a man of one thought [audience laughs]
CH: If you laugh at that, you’re like Bill Mahr’s audience, you’ll laugh at anything.
I don’t like being told that my arguments aren’t as good as his because he has divine information that I don’t have.
CH: There’s an assumption with which I will dispense before the inquiry – there is no supernatural intervention in this argument. Like LaPlace, I don’t need the god-hypothesis.
If he does exist, he is incompetent, absent-minded, capricious and cruel.
This gets to the nub of the issue, and, in my opinion, was the reason that Christopher Hitchens thought he should demean his audience. He does rely on his own understanding – of the world, of Christianity, of himself, of beauty, or morality. Wilson hit the nail on the head. Hitchens sees such reliance as a skeptical process, in which he doubts whatever is useful to him, but this “process” is just another way of saying, “I am my own master, and I am master of all I survey.”

You can watch the debate here.
I thought this exchange was pretty funny — Hitchens makes a good point:

Doug Wilson (DW): Neither one of us has a problem with killing the Amalekites.
Christopher Hitchens (CH): What if I was an Amalekite? It changes everything.