Hitchens makes the usual case that the vicissitudes and suffering on Earth make far more sense on naturalism than on classical theism. He also appeals to certain historical persons and ideas, as is his wont. I didn't find anything particularly striking about how Hitch makes his case, but I've seen him so many times now that it's all starting to blend together, and since there is no evident structure to his rhetoric it is difficult to summarize. At this point, I would challenge anyone to create a formally valid and sound argument using only lines from Hitchen's opening statements, in any order. Seriously, I don't think it can be done.
Dembski does his usual tutorial on intelligent design, and goes on to make the argument that if there is no divine lawgiver then there cannot be any "objective" values that matter at all, to anyone, anywhere. By objective, presumably he does not mean that which is the property of an object (thing) rather than a subject (mind), since only minds can even ponder moral propositions, much less have ideas about which moral statements are true. He must mean "non-human" values, but those don't sound appealing to anyone. Perhaps he means "divine" values, in which case he is simply begging the question. He also makes a few other question-begging arguments, such as God is good because "good" means whatever God wants. At this point, I can imagine the schoolchildren in the audience sending little "ROFLMAO" texts to one another.
As usual, Hitchens excels in rebuttal. "Morality doesn't come in tablet form" is only one of many memorable quips. The Q&A was acceptable, but overall I found this to be a wearying debate, and isn't worth seeing unless you are somehow unfamiliar with the ideas of these two debaters.