I've read most of these, especially the Death series, because I ♥ Death. Hogfather is DEFINITELY worth a read for the Christmas season. It features Susan, Death's granddaughter, after all. The Truth makes marvelous fun of the newspaper industry, Going Postal is an entertaining read, and Thud! is one of the better Watch series books.

Darn, now I need a Discworld icon. That series is awesome.