I bought the Logology Book Andrea posted about a while back and let me tell you, it is the BEST!
SO much stuff in it, packed with more logos than your brain can possible handle at once, all nicely categorized. One thing I find funny is that they organize them by style and put logos that look similar next to each other, which ends up being a little embarassing for some companies because its hilarious to see logos that are ridiculously similar.
Anyway, its worth the money, and bound in leather with orange gilded pages!
edit: Get it here!