Arguably: Essays by Christopher Hitchens - Christopher Hitchens
Christopher Hitchens' last book (he passed away in December 2011) was my introduction to his writing. I would bestow upon this book the ultimate compliment - I expected to hate it, and ended up thoroughly transfixed and delighted with the breadth of Hitchens' knowledge and the courage of his convictions.  It's a brick, but you won't want to toss it out the window.  I promise!