Arguably: Essays by Christopher Hitchens (Twelve, 2011).

Penn Jillette’s book God, No!, which I covered yesterday, opens thus:
You don’t have to be brave or a saint, a martyr, or even very smart to be an atheist. All you have to be able to say is “I don’t know.” I remember sitting in a room full of skeptics when I first heard Christopher Hitchens say, “Atheists don’t have saints and we don’t have martyrs.” I’m a little afraid to put that in quotes, because no matter how brilliantly I remember any Hitchens phrase, when I go back and check, what he said was better than I remember. He is better at speaking off the top of his head after a couple of drinks than I am at remembering his brilliance later while referencing notes.
So onward we must go to the hard stuff, Hitchens himself. While not his first or best collection of essays, it’s essential reading alongside his recent memoir Hitch-22. I interviewed Hitchens when Hitch-22 came out last year, and asked if he’d deliberately downplayed the aspects of his career for which he is, ahem, arguably best known, including his renowned atheism. He admitted that he’d wanted to focus on lesser-explored areas of his life rather than regurgitate material which was already out in print. This fresh form of self-editing meant Hitch-22 was full of surprises. It didn’t get bogged down in wanting to have the last word on old battles, as so many memoirs do.
So here are the parts left out Hitch-22, or the stuff which underscores its last few chapters anyway. It reminds you that you need more than a subscription to Vanity Fair in order to keep up with Hitchens. His collections remind me of another prolific critic and enlightener, Anthony Burgess, who understood the value of a provocative opening line in something as formalized and innocuous as a book review, and who always found room for bon mots amid the brickbats. Hitchens is a professional considerer of things, and here he is in his elements, surrounded by books and clever people and avid readers.