Exhibit B. the master of meta-horror. New Nightmare.
This is what bumps Craven up for me if we're competing on horror/slasher movies - this film both blew my mind and scared the living fukk out of me when I was about 13. Probably the last movie to give me nightmares.
Scream was also a great concept, perfectly executed, that has now been done to death by less subtle film-makers... I still don't know why anyone felt the need to make a cheesy spoof version (Scary Movie) of what was already a glorious fukking spoof movie that manages to be funny AND scary.
Carpenter is the best "director" full stop not just looking at horror though... Dark Star (nobody mentioned this yet?!), Precinct 13, They Live, Escape from NY, The Thing... all classics.