Terry Pratchett belongs in the same class as Charles Dickens-- humor, memorable characters, complex plotting, and social commentary in a prolific body of work. He's definitely developed over time, so his recent work has been some of his best (despite his early-onset Alzheimer's).

"Unseen Academicals" is a good story, ostensibly about soccer. The decidedly un-athletic wizards of Unseen University realize they need to field a team or lose a large amount of money bequeathed to the University. A lowly goblin, whose usual job is ensuring that the wizards' candles are properly dribbly, finds he has a talent that may save the wizards a painful humiliation on the field. And a University undercook is 'discovered' as a model for the new dwarf chain mail (slogan: "No chafing!").

Of course, since it's a Discworld book, it's really about a lot of other things, too. Is biology destiny? What happens when you take someone on as a project, and that person develops a mind of their own? What should society do with the survivors of genocide? Can every group be successfully integrated into a multi-ethnic society? And, most centrally, how can we overcome the "crab pot" mentality that encourages oppressed people to drag each other down or scramble up at each others' expense instead of working together to fix things? This book certainly doesn't have the answers to all the questions it raises, but Pratchett has a rare gift for being both thought-provoking and hilarious.