Brian! Well, it would, wouldn't it?
Norman Bates kebabbing Janet Leigh, then skewering the detective on the stairs in the olde house. Mind you, that skree-skree-skree music added a lot to it!
When the cute baby alien bursts out of the bloke's stomach. "Look, if you were an intelligent species, you'd use the usual method, so you could impregnate Ridley over and over."
Jagged Edge - the opening scenes are very creepy in a realistic way. Glenn Close finding the culprit typewriter later, and trying to get away from Jeff Bridges was also hair-raising.
The presentation of the head-in-a-box at the end of Se7en. I really didn't have this figured until Morgan Freeman looked meaningfully at it, then it was
Scream, the original and first time round, is still truly nasty! Most 'bogeyman' films give you a good startling, though for the repeats, if you put the sound off and you all provide your own dialogue, you can have a bit of fun with them.