Difficult to say. I’ve never been one to fixate on a single film for long. The ones below are likely candidates for various reasons though. I must have seen each at least 6 times. Probably none of them more than a dozen though.

• The Fellowship of the Ring (2001)
• Star Wars/A New Hope (1977)
• Rocky Horror Picture Show (1975)
• Mon Oncle (1958)
• The Ladykillers (1955)
• The Third Man (1949)