The Colour of Magic
Good introduction to the Discworld and it's inhabitants. The characters are interesting because they're new, the humour is less in-your-face and it isn't covered in swathes of footnotes.This first book is a collection of short stories, all following on from each other, following Rincewind the wizard and the tourist Twoflower as they travel the world, meet interesting people and things, and try not to get killed by them.
