While the big four get all the notice there are others hoeing the same row.
Physicist Victor Stenger has a book out: "God, the Failed Hypothesis".
Here's a sample of his writing:

http://www.secularhumanism.org/library/fi/stenger_25_2.html

Also is a new book by mathematician John Allen Paulos: "Irreligion". It's reviewed in today's NY Times:

http://www.nytimes.com/2008/01/22/books/22kaku.html

I read the first one and measured arguments don't sell books (the same point is made in today's book review). That's why the polemicists get all the attention.

Policies not Politics
---- Daily Landscape