I haven't yet read Hitchens' book, but i've listened to several of his debates and lectures. And I must say, I don't think i've found anything he said to be compelling. Furthermore, I don't think i've heard him debate a presuppositionalist. Not knowing much about Wilson, other than being Reformed, I was excited to listen to this debate.
My general thoughts were that of disappointment. This wasn't as much of a debate as it was a "friendly discussion." There was very little structure and little substantive argumentation from either side. I felt that Doug Wilson should have spent more time discussing the basics of presuppositional methodology in a more articulate fashion (like Greg Bahnsen would do). But had he went into more detail (maybe more time was needed?), Hitchens would have been a bit more reluctant to ask, "oh, so the Bible is true because it claims to be true?" or "the Bible miracles are true because you say they are?"
In my opinion, the debate didn't really go anywhere until the audience questions. There you got to see both sides defending in the state of opposition. I believe the turning point in the debate was when Hitchens admitted that the laws of logic were a human construct. When that was admitted, I could hear Wilson chuckling. It was there that Hitchens lost the debate. Either he didn't realize what he said, or he had an amazingly clever defense prepared. Once someone admits that the laws of logic are a human construct, the debate is over. It simply cannot be defended and I would challenge anyone to do so.
More could be said. Although I wasn't too impressed with Wilson, I was happy to see a presuppositionalist finally stepping up to the plate against the "new atheism."
The debate can be downloaded here. Scroll down to the 12th item on the list where it can be accessed.