I liked the tales of Beedle the Bard. These are essentially fables for wizarding kids although muggles such as me who are well versed with the world of Harry Potter can enjoy them too. The stories themselves seem simple, almost childish but it is Albus Dumbledore's expert commentary which makes reading it truly worthwhile.
A quote from the book. Humans have the knack of choosing things which are precisely the worst for them :).
A nice quick read. A must for fans of Harry Potter.
Incidentally I read Beedle the Bard while waiting for my sis at the airport :)