Book recommendation system

I've always liked Pandora, although I don't have time to listen much anymore. I was wondering if something similar is available for books. Although any book (no matter how good or bad) is worth reading, it would be nice to have a little guidance, something like a well-read personal assistant. That's how I found LibraryThing. I guess this book recommendation system is more like last.fm , in the sense that the recommendations are social not stylistic. Google has now it's very own My Library module. Coupled with their online BookSearch project I can envision that we'll be able to read any book anytime anywhere, just with the click of the mouse.