Wendy suggests The Day of the Triffids:
This book is fantastic!! Well written, funny, and an all around good read. Try this first and then read Shades of Grey by Jasper Fforde...another great read clearly influenced by Day of the Triffids.
And Erica offers A Canticle for Leibowitz:
Hauntingly beautiful. I loved the cyclical nature of the world. Death, rebirth, and ultimately destruction occurring over a plodding time frame, where each life is a drop in the bucket of generations. Winner of the 1961 Hugo, this is a classic in the post-apocalyptic genre.
Of course these suggestions are just our attempt to whet your appetite for The Passage, which comes out today! Yay! It's the end of the world! Everyone head to REI!