I've watched a lot of movies based on Stephen King books, and I agree, a lot of them aren't great.  Along with the ones you named, I love Misery and The Shining, although I know King himself was not a fan of Kubric's adaptation of the latter.  The newer It movies are good, too, especially Part 1.  I find the original miniseries kinda cheesy in comparison, although Tim Curry was great as Pennywise.     I have mixed feelings on the original miniseries of The Stand.  Some aspects of it were done well, and some of it was cheesy. The 11/22/63 miniseries with James Franco was okay, but not nearly as good as the book.  I've actually never read the Dark Tower series; I should probably do that at some point, especially if they're making a show out of it.  A show, even if it's a limited series, sounds better than movies.  I think that's why the short stories make better movies, because a lot of King's books are just too big to be adapted into a movie well.