Just finished reading "The Christian Delusion: Why Faith Fails".
It's a great compilation of arguments against Christianity, each chapter written by an expert in the specific topic. It covers material which would usually be spread out in several books. My mother (who is a Christian) offered to do some book swapping, but I've been waiting to find a succinct book for her to read with an overview of the major arguments. I think I just found it.
Go buy it on Amazon and use the TA link while you're at it.