Absolutely LOVED the original version of The Gunslinger, but he released an extended version of it a few years back and it added a lot of extra description and changes that made it hard for me to get through.
Doctor Sleep is awesome, as is The Stand, but if you're ever itching to try new horror authors, check out:
Victor Lavalle - The Ballad of Black Tom \ The Changeling
Grady Hendrix - Southern Book Club's Guide to Slaying Vampires