The beginning of American Werewolf in London is straight scary as all shit! As a kid I also had nightmares for a month after he transformed fully and ate those ladies on the street. Aaah!
As for pure BOO! scary moments....Candyman when the dog jumps up in the window *tv must be loud* and 2003 Texas Chainsaw Massacre when the crazy cop shows up at the car window. *turns pale* guess I'm a sucker for window scares.
