Dinesh D'Souza seems to be the most frequent debater on the "Great God Debate" circuit taking on the likes of Christopher Hitchens, Daniel Dennett, and Peter Singer. If you are interested you can find all the debates on youtube with a quick search.
I cannot find a link to the D'Souza/Singer II debate (I will eventually, though), but here is D'Souza's column discussing the debate, and his surprise when Singer refused to defend his views on atheistic morality, when in fact the debate discussion was "Can We Have Morality Without God?" which would be a topic Singer ought to be adept at defending in the positive.
Also, lest I forget this gem of hilarity over at Atheism is Dead.
Dawkins, Dennett, Harris, and Hitchens have tabbed themselves rather unoriginally the Four Horsemen. Apparently, the starting lineup for the atheist team decided to sit around Dawkins living room with some scotch and discuss the impenetrability and infallibility of their views.
It's a few hours, but if you'd like to see a four men stroking egos and an afternoon spent in frivolity, you have arrived at the correct train station: WATCH!