Horrible elves, Granny at her best (and Nanny), Magrat the killer queen, Morris dancing, stupid wizzards and lots of other stuff - what's not to like?
Probably just because it's my fave. But you can read them and enjoy in any order.
(Along those lines I would also recommend Susanna Clarke’s “Jonathan Strange & Mr Norell” which builds its own parallel history set in the early 1800s Britain, with Fairies taking the same role as elves in discworld.
Yeah, more or less. The “elves/fairies are nice, or at least _good_” thing is a fairly modern creation (owing a lot to Tolkien, really).
Mustn't grumble though, it's not like Jonathan Strange was a pamphlet!