Demento

I'm a fan of Dawkin's writing in general... so I liked The Ancestor's Tale and The Selfsih Gene, too, though they're not expressly anti-Christian. I also liked God: The Failed Hypothesis by Victor J. Stenger.
A hilariously terrible take from the other side is The Language of God by Francis S. Collins (he was in charge of the Human Genome Project and has now been unfortunately placed in charge of the NIH). The unapologetic blind faith is astounding, especially for a man of science, but it will give you a taste of what "opposition" there is.
I've met and talked with Sam Harris (Letter to a Christian Nation and The End of Faith) and he goes even farther than Dawkins in his campaigns against Christianity.

Notice it was a green rep. =)
I couldn't stop laughing (in the "oh, I hate that this even had to be said" kind of way).