I've read the majority of the Discworld books as well as the Bromeliad trilogy and a few of his other, earlier works. I like almost all of what he's written. He's funny above all else, but also clever, suspenseful, creative, and extremely intelligent, especially when compared to most of the other bilge that appears on the bestseller lists.
My favorite footnote is the one about the Monks of Cool, who built their monastery in "an extremely laid-back valley".