I'll just list some that pop into my head... movies that I will stop and watch again, even if I have them on DVD...
The Thing (1951)
Kung Fu Hustle
Day the Earth Stood Still
Streets of Fire
Goke: Bodysnatcher From Hell
Death Race 2000
Any Toho Godzilla movie
Any Ray Harryhausen Movie
Any George Pal movie
Any Hammer movie from the 1960's horror cycle
Any Roger Corman "Poe" movie
Any Gerry Anderson film, Doppleganger, or the Thunderbirds... or even 1999 re-edited into movies...
Number Two: Conform, Number Six! Conform!
Number Six: I will not be stamped, filed, indexed, briefed, debriefed, or numbered! I am a person.