I really enjoyed Thud and am looking forward to rereading it. (I've lent it to someone who really likes it too and was tempted to take off from work to finish it.) I also read Where's My Cow?, which I suspect Pratchett wrote after inventing it for Sam Vimes to read to his son in Thud. I loved how Vimes sometimes made it home by the skin of his teeth to read it on time... I enjoyed Where's My Cow? also; it's illustrated and is more of a children's book, but grownups will like it too!