I enjoyed Dawkins' The God Delusion, but I think people make way too much of it. I am currently reading Harris' The End of Faith which I think is excellent so far (about 3/4 of the way through it now). I read Penn Jilette's God, No! and was underwhelmed. There are a few good points scattered near the beginning of the book, but I think it wanders too much and never really seems to focus on the topic.
"Well, evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape- like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered."
-Stephen Jay Gould
-Stephen Jay Gould