Best book - Goblet of fire
Worse Book - Cant remember the title, but in one of the middle books Rowling changed her writing style to be more 'youth and urban'. It didnt work. Can anyone remind which one that was?
Best film - Deathly Hallow - Agree with TS the books were difficult to follow but the films were fantastic.
Worse film - One of the the mid to late ones, so either Half blood Prince or Order of the Phoenix.