I think Saw kinda' stold some of Dread's ideas from the original book... all the "experiments" were pretty damn similar to something Jigsaw might cook up...
(and since someone brought up 1408, I really try to like the movie, and it does have it's moments, no doubt, but it's nothing compared to the story, which in my opinion is one of King's best works to date. The coolest thing in the story was that the hotel room was haunted, yet, there were no stereotypical ghosts. Then what's the first thing the movie throws in it? That's right... ghosts. Ghosts. Cusack was still perfect casting though, and some of the over the top scenes actually come off pretty cool in their own right, just as long as you keep it seperated from the source material, which had a lot more subtle horrors)