The Complete Calvin & Hobbes.
Because Bill Watterson is a genius. The only problem is, I don't really have any place to put it. :|
I think I have to start a Someday-I-WILL-Buy list:
* The Complete Calvin & Hobbes
* All DVDs of Hayao Miyazaki's work
* Slam Dunk books in English (or maybe I'll buy it now)
* Slam Dunk The Perfect Collection (Japanese comic books)
* All the Slam Dunk tv anime and movie DVDs