Best adaptation from worst source material?

Most King fans agree that the best King adaptations successfully preserve King’s narrative magic from his excellent stories. But even King himself doesn’t always bat 1.000. So what would you say are the best film adaptations from King stories that aren’t necessarily his finest work?

I’ll start by saying that I felt The Night Flyer in Nightmares & Dreamscapes was an okay story, but not top tier. However, I think the film version is spectacular.