Howl's Moving Castle (2004) is a lovely adaptation of the book by one of my favorite writers, Diana Wynne Jones; whenever I hear anyone raving about the latest hot thing in children's/YA lit, I always ask if they've read anything by Jones. JK Rowling wishes she was one one hundredth the writer that Jones is. Seriously.
Now Miyazaki's film isn't exactly the book, but it doesn't dishonor it. They're both good in different ways. Read the book, see the movie.
The problem with the great Japanese animes is that they're so romantic they leave me just crushed when they're over and I remember what real life is like.