Mike asked everyone to put the word out, so here ya go:
If you're in the USA, Click this link and buy some books.
I bought the set, and I would have a hard time imagining a more disparate set of books. There's some incredible stuff in here and, more to the point, if at least one of these doesn't have anything for you, well, you're rather odd. And, to be honest, you can probably flip these at your local used bookstore for a good fraction of what you're paying for them here.
Laughlin: surrealist/double-exposure freak show. So very very southern.
Van Vechten: Portraits of everyone including people I did not even know were real people. Many superb portraits.
Todd Webb: (Atget + Cartier-Bresson) / 2 (the average of the two, sort of) and really nice work as well.
George Barnard: fewer pictures, tons of text, historically very interesting. The pictures are, well, it's not so easy to document an army's movements with wet plate, is it? But for Civil War buffs, practically required reading.