Of the three Gaiman movies I've seen, Coraline, Stardust, and Beowulf, this is the best. It doesn't undercut itself, and the changes in pacing are correct for the medium of film.
In other (and more) words: I had the reaction to the movie Stardust that Gaiman wanted: I loved the movie, but the book is so much better. In the case of Coraline, it isn't that simple. The movie is true to the spirit of the book, and makes changes that work for the screen. There's some stuff I regret got changed, and maybe didn't need to, and there's other stuff that worked better for me in some ways than the stuff in the book. I may go into more detail when I've had some sleep.
In any case, this is the first movie I've seen that really uses 3D well. The three 3D movies I saw trailers for all left me cold. They may be good movies; I may see one or more of them. But, they're all what I think of, snobbishly, as stock Hollywood flicks, sitcom-ish. Having 3D doesn't change that.
But add 3D to something already as solid as Coraline, and you've got magic. And, I hope, box office gold.
It's early in 2009, but the bar for movies is already very, very high.