I see most of my faves have been posted already -- mainly by /u/SeeMarkFly, thank you.
Just wanted to mention a book called "2,000 Years of Disbelief: Famous People with the Courage to Doubt", which contains so many great quotes by so many notable thinkers. There are a wealth of poignant comments in there particularly from the US's Founding Fathers -- which makes it a great resource to have when discussing either state-church separation or just religion's alarmingly-increasing role in our politics here in the states.