Omg, I LOVE Stephen King's books!
Carrie, IT, Misery, The Dark Tower series, Cujo, so many good books!
Also some stinkers, like Cell.
I'm reading The Stand right now!

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As for movies, I liked IT when I was growing up, despite how cheesy it looked (and how far it strayed from the book, but whatever) and I hear there's a remake in the works (but it's been in the works for QUITE SOME TIME NOW, it may never come...)
Carrie was good, and I even enjoyed the made-for-TV remake.
Never actually saw Cujo.
LOVED Misery.
Oh, there's so many...
EDIT: THE MIST! Such a perfect adaption!