Woo for good research as well, B.
I had known about Einstein and Jefferson, but to be honest, I posted the image anyway, because I thought it was a funny enough concept, even if a bit unrealistic when it came to the particular concept of their beliefs.
The Ben Franklin quote you found was awesome, you completely had me there, I had never read that anywhere, so thanks for that.
I have read enough Twain to have conflicting notions as to his beliefs as well, but I'd likely peg him as agnostic, not athiest. He was close to being an athiest, though.
I myself am agnostic, but I used to be an athiest. As often as I can, I disregard the issue of God entirely, but she/he/it almost certainly exists, though we likely know nothing at all on the subject.