The New York Times asked Penn Jillette about his reading habits and he managed to squeeze in more atheist references than I thought humanly possible in the paper of record:

If you could require the president to read one book, what would it be?
I’m not big on government requirements, but I would suggest “God Is Not Great,” by Hitchens. It would be good for the country if the president could be seen reading that. Even better if that president is Romney — maybe he’d lose the funny underwear.
…
You’re in charge of setting a college student’s freshman-year curriculum. Your list of required reading… on religion?
The Bible — cover to cover, without someone alibiing it. Just read it. Nothing will turn you into an atheist faster.
…
What’s the one book you wish someone else would write?
A great biography of James (Amazing) Randi. I love him too much to do it justice myself. I have no perspective; he created me.
I also learned more about his naked reading habits that I ever really wanted to know.
You can read the full interview here.
The paperback version of Every Day Is an Atheist Holiday! comes out this October.