I agree wholeheartedly with Stir of Echoes. Really shit me up.
In fact, I am going to add The Ring (remake), cuz everything about it creeped me out, though I dare say I will upset a lot of people here.
Oh, and The Thing. Still probably the scariest horror film I have ever seen.
Les Diaboliques should also get a mention for being 50+ years old and still able to shock!
Anyone mention The Orphanage?