i voted king, not because i don't think that poe was a groundbreaker and that lovecraft isn't creepy, but because i remember being horrified by far more king stories, and remember them too. The only lovecraft i remember clearly is "The Colour" , and poe is all one mass of similar stuff in my mind. Barker i just couldn't get into; may try again tho.
Just one recent example; I love (!
!) the first few chapters of Dreamcatcher, because of the body, the body as source of fear, (like in Cronenbergs film "The Fly"). It's done better in the book than the film where it is too quick. In the book it is terrifying , the creeping dysfunction of the lost hikers body. Afterwards the book degenerates. A lot of kings best horror is about the body and the ordinary going wrong, whereas poe and lovecraft are too abstract for me.
Koontz, on a good day, like the woman with twins pretending has only one son, because is supposed to have adopted only one child and so one must always hide away. They experience themselves as only one, grow up thinking that they are one person, but in two bits. At his best Koontz writes horrifying stuff about mental torture.
I actually find M R R James' ghost stories pretty horrific too, body or not. That "hand" on the corner of the chair. brrr!
And there is also "Frankenstein" by Mary Shelley, before either poe or lovecraft. Trying to bring "a body" back to life.
