Totally agree about GEB. But I never understood what I was supposed to get out of Pirsig's Zen and the Art of... I always felt like I was missing something that everyone else connected with. Do you remember what you connected with in it?
I was a young teenager when I read it, and had not yet read Plato, Aristotle, or any Zen, so it was a nice eye-opener, but quickly superseded.
I'm guessing "The Matrix" played a similar role for a more recent generation. If you haven't been previously exposed to Philosophy 101, I'm sure it seems pretty profound.