I love his earlier books and his short story collections. I also enjoyed the Bachman books. I think King is a wonderful storyteller and he has the ability to imbue everyday objects and events with a frightening sense of the sinister. I think he's very good at constructing believable characters. I get a clear picture of who these people are when I read about them.
I was not impressed with The Stand, Dreamcatcher, Gerald's Game, From a Buick 8, Desperation and The Regulators. The Black House (that he co-wrote with Peter Straub) was a huge disappointment. I only enjoyed the first story in Hearts in Atlantis.
The Bachman novellas were outstanding, especially Rage, The Long Walk and Apt Pupil.
I loved Rita Hayworth and the Shawshank Redemption.