Your going to love F.E.A.R. All I can say though, is save it for the dark nights. Shut off all the lights, and have the 5.1 ready. I guarantee you the opening scene will freak you out.
F.E.A.R. Is a really good game for the PC. I hear its easy for the 360 though. Oh, and the last level and ending of F.E.A.R. is pretty sweet. All I have to say, is wait until its dark, have the lights out, the Bawls chilled... oh, and an extra pair of pants

(I can't guarantee it will scare you, but its freaky)