I think the only time I've loved the film more than the book is Howl's Moving Castle, where Miyazaki's film has a much darker take on the universe than the Diana Wynne Jones original -- but in that case I saw the film first. They are so different it would be easy to consider them different takes on a similar idea that happened to use the same names.

Though there are some adaptations that provide wonderful eye candy for the heterosexual female/gay male -- Maurice and the television version of Brideshead Revisited spring to mind.