Excellent article. I'm so glad you finally watched this. I still can't make up my mind whether I consider it a horror film or a thriller. Both, I'd say. My wife was definitely freaked out by the twist ending when she first saw it (as was I - didn't see that coming at all). But that doesn't necessarily make it a horror film, I agree. Still, that last ten minutes or so is absolutely nail-biting.

Random side question: Have you ever seen Coma (the 1978 Genevieve Bujold/Michael Douglas starring version directed by Michael Crichton - not the more recent TV remake)?