It depends on what you value; I'll address some of the best I can think of for a given characteristic:
---No one matches Mr. King's attention to the "unnecessary" detail in his characters' lives. Even 2-page characters are given some development that makes them forever live in the reader's memory. (Remember George Meara, the farting postman in Cujo? Yes, I knew you would!)
---For historical fiction, you could try Bernard Cornwell. He's been around forever so you may already know him. Unparalleled researcher; I checked with a friend who is a PhD in History at a prestigious university, specializing in England, and Cornwell gets everything right (unless he admits an intentional boo boo).
---Dialogue.... good dialogue is hard. One of the best I've seen is kind of a surprise entry, Gregory McDonald. His work never got a great lot of highbrow respect but won a couple of Edgar awards. He is the author of the Fletch series, which (surprise, surprise) is a lot better than the Chevy Chase movies made from it. Although the movie is pretty good too.
---Straight suspense (non-supernatural, non-military, etc.) Unfortunately, his output is small (and staying that way since he died years ago), but Joseph Garber wrote a heck of a good yarn. When I first read Lee Child, who I love, I thought, "Jack Reacher is just a slacker version of Dave Elliott from Vertical Run." I wanted so bad for Dave to get a sequel, or at least a movie, but no dice.
---Humor...I grew up in the 80s, so I'm going to date myself here, but Patrick McManus was a heck of a funny writer for Field and Stream, and collected years of columns in several volumes. I mean, true laugh out loud funny! Then nothing much for a long time, and now he's writing droll, fun detective novels. Check them out.
---More horror... a lot of us love Dean Koontz. I suppose I like him pretty well since I've been reading him since the mid 80s and still do. That said, I don't feel the need to read every one, and he sometimes gets so pompous I can't finish the thing. He has an admittedly better vocabulary than I do, and loves to show it off. He never uses a 10-cent word when a fifty-cent one will do. Odd Thomas excepted, his best work was decades ago.
---Slasher comedy/mystery (?)...Yes, it's a category. So there. If you watched Dexter on TV, do yourself a favor and read them as well. Jeff Lindsey has a remarkable gift for writing that inner dialogue of characters that Mr. King does so well. And he's absolutely hysterical at the most unexpected moments. Another standout in this category is Tim Dorsey, who writes a series about an ADHD-type serial killer who loves Florida history. It's unexplainable; just try it. I recommend Atomic Lobster, Nuclear Jellyfish, or Gator A-Go-Go if you want to just dip in.
It's bedtime, but if I think of anybody else I love, I will add them in.