The Dino DeLaurentis movie was pretty awful, however, I think that the worst rendition of a book to a movie award goes to "Starship Troopers." Granted, it's a really fun movie that I enjoyed immensely, but other than the title and some character names, the book and movie were pretty much two completely different stories!
Mark
Starship Troopers: based on the back cover of a novel by Robert Heinlein.