An extremely interesting debate between Michael Shermer and Dinesh D’Souza.
Part 1: Monologues
Part 2: Dialog
For what it's worth, and for my own part, I think D'Souza "wins" the debate hands-down. D'Souza is the better speaker, more natural, and comes across as more reasonable. He's also more focused on the core aspect of the debate. He looks at the bigger picture of values that are central to all denominations of Christianity, and what the world would be like if the world didn't have those. He makes a compelling argument that -- even today -- those areas of the world that do not share those values are worse for it. He also makes the startling observation that -- for all the reputation of the Inquisition, the Crusades, and the Salem witch-hunts -- less than 3,000 deaths worldwide in all of history can be directly attributed to persecutions perpetrated by Christians; vs. the hundreds of millions of deaths ordered by atheists such as Stalin, Hitler, Lenin, Pol Pot, etc. Through examination, he shows that widely touted "religious" divisions (such as Northern Ireland) are for reasons other than religion.
Shermer doesn't tackle the central question at all, instead trying to divide Christianity into "good" Christians, "bad" Christians, nit-picking and cherry-picking, and spending an inordinate amount of time on the single subject of gay marriage. He continues to hold forth as examples the Inquisition and witch-hunts, which were already defused by D'Souza. He also tends to speak to points which are outside the common experience of the audience.