I got into Clive Barker a while ago through both Undying and the Hellraiser movies. In fact Coldheart Canyon was the last book I ever read in entirety, and I think he works better as a fantasy writer than of horror (I started reading Everville in college but have been unable to pick up a copy since then). Stephen King is certainly the modern day horror Guru, not only because of his fascinating concepts, but also his ability to manipulate the reader (I think Cuju was quite a good example of this).
Horror is a very strange genre to me. it has a deeply psychological gravitas which I don't completely understand myself. I'm not sure it's voyourism, morbid curiosity or just a safe, secure outlet for out own anxieties and negativity. I'm afraid I havnt' read many Horror books, though I imagine they would be superior to movies (sometimes your imagination is worse than anything you can see on screen). I must say that I do like a bit of Lovecraft, and prefer him over Poe. This is becuase I view them as very different writers and storytellers. From the few Poe stories I've read, I gather that he was aiming for a far more human horror, dwelling on man's capacity for evil and madness (c.f. the tell-tale heart) but then I haven't read much, so correct me if I'm wrong. Lovecraft, in comparison, draws on man's insignificance in the world, that there are big, evil forces that are hiding just below the surface, waiting to enter our world and crush the human race out of existence. Much of his skill comes from his disturbingly easy ability to make the incomparable uncomfortably comparable, and the level of "this-is-far-to-hideous-and-evil-to-be-comprehended-by-the-rationality-of-a-sane-mind-ness" he gives his writing. the two are at completely different ends of the spectrum. In a funny way, I think Lovecraft and Poe are like theism and atheism. Lovecraft implies that human affairs are insignificant in the full scope of the universe, and that we should live in fear of the great unknown. Poe, on the other hand, implies that evil is internal, a part of the human condition, a part that many fear in themselves ( again, I could be completely wrong, I'm just clutching at straws here).
Personally, I consider Poe's ideas to be the closest to the truth, however, when it comes to fiction I much prefer to have my imagination put to the test trying to grasp the idea of a supernatural source of evil and darkness, so I suppose I have the best of both worlds.