Awhile back I wrote a post about similarities I saw among the skeptics with which I interact. One of the similarities was the fact that matters of religion and faith tend to be of great importance to them. They often were highly involved in religious life before their deconversion. A recent survey would appear to support this observation. You can read the article here.
The survey found that atheists and agnostics are significantly more knowledgable about the Bible than Christians. In the article the author writes, "American atheists and agnostics tend to be people who grew up in a religious tradition and consciously gave it up, often after a great deal of reflection and study, said Alan Cooperman, associate director for research at the Pew Forum."