I saw Halloween when I was way too young on broadcast TV. Scared the pants off me then, and it still does now. Not being a slasher fan, it's the only film in the genre I own, and yet I can rarely bring myself to watch it because I'm creeped out for days afterward. But it's more Psycho than Nightmare on Elm Street, leaving the vast majority of the fear to your imagination.

Edit: But this isn't a thread about Halloween, it's a thread about the man who brought us the entire series, and his tragic loss. I have to respect the man.