Last month I read "The Road" by Cormack McCarthy (the guy who wrote "No Country For Old Men", recently made into a film).
"The Road" is a post-apocalyptic horror story, all the more horrifying because there are no monsters.
The story takes place about 5-6 years after the world has been destroyed by some unnamed cataclysm. At first I assumed it was a nuclear holocaust, but as time went on the descriptions of the devastation made it seem more like a catastrophic meteor strike: the skies are eternally gray, mountainsides are scorched, ashen dust covers everything, even clogging the oceans. Almost everything is dead, nothing will grow, and the few human survivors band together in groups of cannibals and scavengers.
A man and his young son are following a road south, desperate to find food and avoid cannibals. They witness horrifying scenes of destruction and cruelty, and the book is relentlessly despairing. It is really hard to see how any redemption can be pulled from the horror. Bleak doesn't even begin to describe this story. I really dreaded the end because it seemed to be leading only into deeper tragedy.
In tone the book reminded me of the darker works of Harlan Ellison, but without the fantastical elements. I read a lot of Ellison in the 1970's, and found the nihilism perfect for my teenage years. McCarthy is a more disciplined and controlled writer than Ellison, and thus his horrifying story is much more believable.
McCarthy has been described as one of the greatest writers in American literature. His story was so sparingly written and so evocative of an imagined place and time that I think I'd have to agree.