I've read some of his books. The Stand was the first major story that I read of his (and my personal favorite) but I saw the miniseries first. I've seen the movie/tv adaptations of a lot of his novels, which I've mostly enjoyed. I do like to go back and read the novels upon which they're based when I have the chance.
Firestarter (saw movie and spin-off miniseries "sequel")
The Stand (seen miniseries and read book)
The Shining (seen miniseries and read book)
The Mist (seen movie- based on novella)
The Langoliers (seen miniseries and read novella)
It (seen most of the movie)
Needful Things (seen movie)
Hearts in Atlantis (seen movie)
The Green Mile (seen movie)
Misery (seen movie)
Most of his stories are overall pretty good and have an interesting and often compelling combination of the normal and paranormal. Although not religious per se, he does seem to work in a small amount of spirituality into most of his stories as well that make the stories and characters slightly richer.