Well, Robert Frank's
The Americans is about as close to a classic as you can get. There also happens to be a pretty good edition in print right now wo you can get it pretty cheap. The thing with fine art photography books is that they're not continuously printed so availablility has a lot to do with what book you choose. The Online Photographer has been my main source for photobook suggestions. You can browse through the posts tagged with
"Books" to get a few ideas.