I've read the Neuromancer , it's a good book. John Saul and Dean Koonz are two good authors of thrillar/horror with out a lot of romance.I recently started reading Neuromancer by William Gibson. If you're unfamiliar with his works he does cyberpunk stuff. So far the book is pretty good, but when I'm reading a book period I don't really like sex scenes.
Avoid Christine Feehan, if you don't like romance. Her Carpathian series about Carpathians (vampire-like being except they love and have souls) who hunt down rouge Vampires(Carpathians that have lost their souls and hunger for power and killing) has lots of action but just as much heavy romance. (This would be great for thous of you who love romance and thrillar/fantasy)