Bentley Little always manages to creep me out a good bit, as well, with his bizarre settings and even more bizarre monsters, e.g. the frizzy-haired Mogollon Monster of "The Return."
Edward Lee, too, with his mysterious, deserted island settings and slimy worm-like things that like to invade the human body and control the human brain.
There are lots of other creepy modern-day horror writers, too, like John Saul, Douglas Preston & Lincoln Child, Brian Lumley, Ramsey Campbell - well, you get the idea.
But all of these writers were inspired by other writers that came before them, just as I was, and two of the most influential of them are Edgar Allen Poe and H. P. Lovecraft. Those guys practically invented creepy.
Take, for example, The Tell-Tale Heart. The sound of the thumping heart, the milky-white eye of the old man, the way the beam of light shone on it just so, just enough to see the eye and nothing else. Then, the sound of the old man's heart beat - after he's been killed.
Or how about Montresor walling the poor Fortunato in the wine cellar? Talk about keeping the lights on!
H.P. Lovecraft's descriptions of the dark recesses of the cosmos and of beings so alien that any similarity to humans is non-existent, is some of the most disquieting reading ever. It's so slow it makes Stephen King's "IT" look like a roller coaster ride. But it's major creepy - you almost have to put the book down just to digest the weirdness of it all to continue reading. He's the guy that invented the "Cthuhlu Mythos" and the Necronomicon, or Book of the Dead and wrote for lots of pulp magazines in the 30s. The man was not much for dialogue - there's hardly any talking in any of his stories - but believe me, you never miss it. You're too busy getting creeped out by "The Whisperer in the Dark" or "The Colour Out of Space."
But there is one book that I have yet to read because it creeps me out so much I can't even get past the first page. It's by Shirley Jackson and it's called, "The Haunting of Hill House." Want to know why I haven't read it? Because I've never been able to get past the line, "...and whatever walks there, walks alone."
That, in my opinion, is one of the creepiest lines in all horror literature.