Don't know why I'd want to know about more of these, but somehow, I do. My choices:
On the Beach, Nevil Shute. Even less uplifting than I thought post-apocalyptic fiction could be.
The Mayor of Casterbridge, Thomas Hardy. Is this even Hardy at his worst? I've heard Jude the Obscure is fairly unbearable. Anyone read them both?
Dying Inside, Robert Silverberg. This one's less well-known. It's about a middle-aged guy who's losing the ability to read minds (which is much, much worse than never having been able to read minds in the first place).
Any other nominees?