Dean Koontz is like Harlan Ellison. When you first start reading him, you think he’s pretty good. Then, as you read more, you realize you are reading the same stories in the same style over and over again, and it can get tiring. But though I’ve read a lot of his books and say I’m tired of him, if someone gave me one I hadn’t read I’d probably finish it in a day or two. If you’ve never read him before,pretty much anything of his (except for that screwball comedy one that I forgot the name of) is a good introduction to him. Keep reading until you thing ‘This seems a little familiar’ and STOP THEN.
BTW, he was a science fiction author when he started out, and a lot of his horror has SF elements. I read an amazing short story in ‘Again, Dangerous Visions’ that he wrote in 1970 that would have led most people to believe he was going to be a big name in SF, instead of a successful hack horror author.
Clive Barker is pretty awesome. His later work has moved away from horror and towards dark fantasy (and it’s damn good), and it may not be to most people’s taste, but his earlier work was very imaginative and evocative horror. Clive Barker has left many disturbing images and ideas in my mind that will probably never leave me.
I’ve read some Anne Rice, but that doesn’t really seem like horror to me (except the horror I feel at how bad some of it is).
A lot of people talk trash about her, but Poppy Z. Brite’s first novel, ‘Lost Souls?’ was pretty good in my opinion. Someone could describe it as Southern Gothic + Vampires, but the setting is so fully realized and detailed that it almost feels like science fiction with the vampires being an interesting alien race, which is evolving to become more and more like it’s prey - each generation is less powerful than the one before, but also lacks some of the weaknesses that kept other vampires from being able to mingle with humanity (i.e. inability to drink alcohol, sensitivity to sunlight, etc.). I’ve tried to read one of her later books (‘Drawing Blood’, abominable) and I read a collection of her short stories (mostly bad), but ‘Lost Souls?’ is worth reading. She shoulda pulled a Harper Lee and stopped before we realized that was the only good story in her.
The only thing by Straub I have read is that collaboration he did with King, which I didn’t care for (and I like most King, even some of the ones that most people hate like Insomnia or Rose Madder. I can’t think of any other horror authors (oh, except Lovecraft and Poe) but I’m sure more will occur to me.