Different Seasons
Different Season is King's best work (that I've read).Almost nothing fantastical here. Just good old good storytelling (with the possible exception of "The Breathing Method").
I've always felt that with such abundance of ideas (loads of crapola too - but that goes without saying), King if anyone should stick to writing novellas.
Writing short stories (well.. the term short is obviously a very relative concept to Mr. King) honestly seems to be the only way to stop the man from tediously describing every scene so that in the end most if not all of his novels contain at least 200-300 pages of details that we could very easily manage to do without (or imagine for ourselves).
I think that one reason King chooses to write horror, is because he is not comfortable of showing his political leanings and views (that each and everyone of us do have). There's always the possibility that being more openly political might kill the milking cow.
In this context, choosing to write horror is the safest genre of writing - that is unless you are writing to children. After horror, writing detective stories is the next safest choice: that way you can at least give the impression to the readers that you have something important to say about something that ain't right (even when the author would be talking more or less out of his - or her - ass).