Regarding movie -> film adaptations; I haven't actually read any Dahl which I know is a huge literary misdemeanor, but I have to judge films on their own merit. I mean, there is no way that The Road (as a movie) can do justice to McCarthy's book, but the movie may stand on its own two feet (haven't seen it yet...)
Fox (the movie) definitely stands as its own entity--it neither contradicts nor undermines itself. It is brisk and thoroughly entertaining. Maybe not the same as the book, but the director did quite a bit to keep it in the spirit of the thing. Oh well, it will be gone before people are done swooning over twilight.