I enjoy short stories the way I enjoy the Twilight Zone -- I look forward to the end and the final twist. But a novel allows you to enjoy each turn, the stories within the stories. It's like LOST verses the Twilight Zone.
One reason The Stand is such an engaging novel is that it is long and takes the time to build characters. King's novels are usually a series of short stories pressed together into a larger plot. Ray Bradbury literally wrote the Martian Chronicles as a series of shrot stories.
I do wish the Tommyknockers were a novella instead of a novel.
Here is a quick list of my favorite King short stories:
1. The Mist.
2. Riding The Bullet
3. Autopsy Room Four
4. Dolan's Cadillac.
5. Suffer the Children
6. The Ledge
7. Survivor Type
8. The Girl who loved Tom Gordon.
9. The man in the black suit
Okay, so the Mist is techincally a novella, but it's in a book of short stories!