To the book-store!

Hello, I'm going to go to a local used book store in a short while, and I'm curious as to what books you guys would recommend.
I'm mostly interested in Post-Apocalyptic Science Fiction, but other suggestions are quite welcome.
Thanks.

How's this for post-apocalyptic scifi?:

  "Aristoi" by Walter Jon Williams

They destroyed the Earth with rogue nanotech.  How's THAT for an apocalypse?

lets see.....try The Road by Macarthy......also Oryx and Crake by Margaret Atwood is good.

HHGttG

If you love science fiction, check out the sci-fi anthologies collected by Gardner Dozois. They're never over 10 bucks at used bookstores, which is great.