The Dark Half - I read several times, but Dolers Clairborn was very clever stuff.
And Insomnia was a real head trip.

Yeah, I do think that of his more recent stuff, it was quite good. It was nice to read something that wasn't overdone.

Roadwork.

Surprisingly effective character study in emasculated male power, identity, grief, and despair on the backdrop of the 1973 energy crisis. The real horror in this novel was that of George Barton Dawes failed life and his desperate stand against suburban irrelevance, symbolized by a highway bypass. I always thought Stephen King was best doing "straight" fiction, like with Misery, or mostly-straight, like Rose Madder.

Now that I think of it... I have only read "The Stand". And it was awesome. So there is my answer.
The Stand is also my favorite of all the movies and mini-series based on his books, by a pretty big margin.

It's a toss-up between The Long Walk and Low Men in Yellow Coats from Hearts in Atlantis, with the Castle Rock series (sans The Dark Half) in third. Under the Dome was alright but the ending was too abrupt for my liking after reading 1000-odd pages of story.

I was going to say the entire Dark Tower Series (which ranks up there amongst my favorite all time reads along with LOTR and Asimov's Foundation Trilogy), but if pressed to pick one book of his, I have to say Wizard and Glass was a standout, story telling masterpiece

Yep, I prefer his short stories too.

I've read... let's see... Swedish translations of Dreamcatcher and Insomnia, Bag of Bones and The Dark Tower (the series, minus the recent interquel).

Of the bunch, I found Bag of Bones to be immensely enjoyable right up until it suddenly ended, but The Gunslinger (the revised version) beats it by a wide margin. I'm not sure if The Dark Tower (the book) ranks second or third on that list, but The Gunslinger definitely wins.

Agree with both - love the Dark Tower Series and the graphic novels have been great!

Also, The Stand was the first of his books I read (wonderful stuff!).