mm....
dawn of the dead (new one)
day of the dead (new one, don't know if there is an old one)
saw (it was just twisted kinda falls under "it scared the shit out of you with out showing you any thing it was the thought that fucked with you.")
i can't really think of a 5th favorite, i guess i'd have to say candyman, but only because i watched it when i was 7ish and for the next few years you wouldn't catch me dead in the bathroom with the door closed, nor would you find me ever look into a mirror.