I've got a bunch of favourites, but here are my tops. In no particular order.

-This is Spinal Tap (1984)
-Animal Farm (1954)
-Apocalypse Now (1979)
-Citizen Kane (1941)
-The Shining (1980)
-A Clockwork Orange (1972)
-Prince of Darkness (1987)
-The Thing (1982)
-The Fog (1980)
-Halloween (1978)
-Dawn of the Dead (1978)
-Texas Chainsaw Massacre (1974)
-Pet Sematary (1989)
-The Evil Dead (1983)
-The Fly (1986)
-Mary Poppins (1964)

Yup, Mary Poppins. I said it.