I've been following the SNOWBRUSH blog for quite a while. Snowbrush is the screen name of a man who grew up in Bible-belt Mississippi and now lives in Oregon. He has been blogging since 2003.
There are several posts on his blog explaining his religious and non-religious background, including his post of 5/12/10, "Does God exist? Why I think the answer is no" which is a well-thought-out explanation of his reasons for being a non-believer.
Check it out and while you are there, check out some of Snowbrush's other posts, too. Snowbrush is an interesting character and has many tales to tell.