of horror marketing theories and medicom's 1/6 hostel figure

what makes a great memorable horror/slasher flick? okay, screaming half-nekkid-hawt-ladies work alright (just before they get killed and bloodied, innit?) and sure, the blood-spill and killing and whatnot, the drop of a glass before the monster grabs you by the throat, the rush of the wind thru the window before you get stabbed in the chest or back ... but what makes a memorable and "marketable"