I voted Fatal Frame.
Fatal Frame 2 is hands-down the scariest games I've ever played. I can't play it at night because I screamed too much, and well, living in an apartment like I do the neighbors didn't appreciate it.
All of the games listed have their fair share of scares. I would also add that
Haunting Ground for PS2 is a scary game. Deeply disturbing and not to be played around the young ones.
