My favorie (and the best adaptation) is Pet Sematary. Fred Gwynne as Jud was perfect casting and the director really seemed to understand what made the book so effectivly scary.
One adaptation I hate (save for the wonderful Overlook Hotel interiors) is Kubrick's The Shining. He either missed, or ignored the real subtext of the book (alcoholism can destroy a family) and Jack Nicholson's hammy "crazy" act that he does from the begining doesn't help. The TV movie does the book much better justice.
Oh God what a horrible list this will be. I almost never think of any of his books as 'good' adaptations, let alone movies. Misery was very good and obviously Shawshank, but the other end of the list is just awful. The Stand & Tommyknockers were terrible movies any way you want to categorize them, adaptations or not. The *VERY* bottom of the list should abolutely be Dreamcatcher .
Out of the TV ones, I liked the Stand since it really didn't leave much out, we can argue about the ending, but it hit on every mark and is my favorite King book. The best movie is Shawshank even though its just a short story, but Green Mile isn't that far off in my book either. I hated Storm of the Century even though it was just a made for TV thing. I agree with Dream Catcher that was garbage and seemed like he was combining Tommy Knockers and Stand Be Me for some unknown reason. I have to say I enjoy most of the movies like Carrie, Christine and Needful things. I actually prefer Needful Things the movie over the book. Most of Kings' movies and TV stuff is pretty good, but when you have about 20 pieces of work out there, you will get some clunkers.
Though I've read plenty of King, I haven't watched many adaptations because I mostly stick to comedy and blockbuster action in my movie watching habits. However, I remember The Mist as being excellent, with the different ending being better than King's original one.
Lloyd: When I met Mary, I got that old fashioned romantic feeling, where I'd do anything to bone her. Harry: That's a special feeling.
For those of you who like "So bad, they're good" movies, Pet Sematary II is pretty damn awful and cheesy.
I find it sort of funny that the Wikipedia article I linked to counts "The Lawnmower Man" movie as an adaptation of King's work (he sued to have his name taken off of the movie's title because it has nothing to do with his short story of the same name).
I just want to second that comment about Morrison's run on New X-Men being way, way awful. I hadn't been reading comics for a while, but heard great things about this title, so I bought the big hardback collection of it.