The part in RE4 when you first meet a Regenerator is possibly the most heart-stopping, fearful moment I've experienced in gaming.
I completed a few of the Silent Hill games and whilst they are disturbing, any of that is removed by the fact that you know the pace isn't going to quicken and make you panic. It's a safe fear, not an unpredictable one. You never know what's gonna happen in RE 4 really. Especially since the scenery and enemies change so much.
Who can forget walking into the castle and having the raspy breathy monks close in on you? Not me.
-AC