He was indeed a great guy, aside from being a fantastic author. I grew up in southern california, and every year he would come down to my small local library to give a talk, sign books, and generally hang out. As a child I got to spend hours with one of my literary heroes, including tons of one on one talks on various topics. He was very inspiring to me.
He'll be missed - but not mourned. I don't think he'd want that.