One of the most common things I see said to my atheist friends by their Christian friends & family is attempts, via various tactics, to shut them up. They don't like it when we speak up about religion. They especially do not like it when we do so effectively.
No one did it more effectively than the late Christopher Hitchens.
In initially planning for this list, I was not going to include any of the Four Horsemen. But when I switched it to be personal to me, leaving Hitchens out ceased to be an option. He pointed out the absurdity of what religions expect us to believe with unmatched eloquence. He condemned religion, with veracity and without apology, for the evils it contains and attempts to force upon us.
He did this so well, the act of him doing it was given a name. Hitchslap.
Christians tried relentlessly to shut Hitchens up. He, as he would put it, was having none of that. They also attempted to outwit him. They failed miserably every time. Even as he was dying of cancer, he refused to stop until the cancer forced him to.
As much as I admire James Randi, the atheist debater I most wish to emulate is Hitch. I share his disdain for religion. And while, I'm not likely to ever attain his level of eloquence (not many will), I don't plan to let that stop me.