The very first book I ever read from the Master of Horror would have to be my favorite as well, The Shining.It was the novel that led me into his universe of twisted tales.Alot of others come in a close second though. Such as The Stand, Misery, The Talisman and Black House (w/Straub who is also a great author) .
As for his short stories, I loved "You Know They Got A Hell Of A Band" in Nightmares & Dreamscapes. This is the one where the main characters, Mary and Clark Willington, get lost on the backroads and find themselves in a small town named Rock & Roll Heaven. I loved the idea of meeting the ghosts of Jim Morrison, Janis Joplin and Elvis.
Another one of his shorts that I liked very much was "The End Of The Whole Mess". It was also published in Nightmares & Dreamscapes. The story was of a man and his genius brother Bobby. Bobby found a cure for the inhumanity in man in a aquifier and had it arranged to distribute all over the world. He overlooked one important thing , that the water causes a major drop in peoples IQ's

In essence, Bobby turned the whole world into idiots.
The made for TV movies that are produced from his novels are sometimes hard to stomach.

But that's a discussion for another time.
Cheers to all!!!