I read "Way of the Peaceful Warrior: A Book That Changes Lives" back in high school, and it made a profound positive difference in the way that I view the world.

I recommended it to my roommate a few years ago though, and I read it again after he was done and found it to be super cheesy and slightly pretentious. My roommate seemed to like it, but I don't know if I would really recommend it to a grown adult anymore.