Or at least what has been written so far? I think there are two books still to come on the latest set.
He is the first fantasy writer I ever read who didn't have dragons and wizards and he has always been one of my favorites. I started reading these when I was about 14 and they probably had more depth than any other fantasy books I had read to that point and they made a big impression on me.
I liked the idea of a hero so flawed and weak but at his core strong and hard enough to win and I liked the idea that he didn't do it to be heroic but because he felt he had no choice. That and Blood Guard and Giants were awesome.