Stand By Me, 1986 - Based on Stephen Kings novella ..
The Body.
Not only is this my favorite book turned film by King, but, also my favorite all time film in general. Rob Reiner did an incredible job of getting astounding performances out of all of his cast. If you watch the bonus material on the DVD you will see that he really goes to extreme lengths to drag out the potential that he knew he had found in the four young actors.
What else is perfect about this movie? The camera work, the narration by Richard Dreyfuss, the clever use of period music, the attention to detail (like the old Hills Bros. coffee can the kids pitch rocks into at the junkyard), the pace and rhythm. The juxtaposing of the main storyline with detours like Vern's penny hunt and the sad but hilarious tale of Lard Ass Hogan is brilliant, and makes this a hard film to get tired of no matter how much you see it.
One excellent scene in particular, the real gem in this crown, is where Chris (River Phoenix) tells Geordie (Wil Wheaton) about his milk-money experience. It was the strongest point of the film, by far the most emotional and River Phoenix acted well beyond his years, more believable than most adult actors.
To give this film as high praise at it deserves is near impossible.
Apt Pupil, 1998 - Based on Stephen Kings novella of the same name.
It does so primarily because writer Brandon Boyce and director Bryan Singer have wisely ditched King's by-the-numbers gore in favor of a far more interesting focus on the characters.
McKellen and Renfro put in outstanding performances as the leads. Renfro strikes the perfect balance between innocence and menace, and McKellen is at times legitimately terrifying as the aged Nazi.
Overall, this is more tightly constructed than the novella, and dispensing with the ludicrous violence makes it far more credible. For these reasons, it's more unsettling than King's work could ever be. Once again Singer has given us a cleverly written, beautifully acted, and finely crafted film.