I would have to say my greatest influences in writing would have to be V.C. Andrews and Chuck Palahniuk.
What I admire about V.C. Andrews is that she knew how to write a book where the reader didn't feel like they were reading, but instead watching a movie. Her pacing isn't too slow and it isn't too fast. Just perfect. I also love how she was able to capture such a disturbing taboo subject and told it in such a way that it felt justified (incest.) Andrews also knew how to write a scary story without making it scary and over-doing the fucked up factor.
What I admire about Chuck is just the opposite. I love that he makes puts the reader in a fucked up punch bag and doesn't stop throwing punches. I also love the cynical, honest narration in which he tells his stories and the wit it possesses. However, one could argue that the voice of his narrators teeter on the fence of being flat-out pretentious. But, eh, I love it.
What about you? What authors influence you?