The A.V. Club had a feature asking a bunch of people I've never heard of the question "what's your most-rewatched movie?" Their responses were interesting—and would be more so if I were familiar with the individuals—so I thought I'd share my answer.
I've thought about the subject a lot because my favorite movies aren't necessarily the ones I watch regularly. It's a crucial distinction because there are several movies that I don't think are good or great by any stretch but I enjoy watching a lot. My favorite movies aren't necessarily those that I can (or do) watch regularly but they really resonate with me whenever I do.
My all-time most re-watched movie has to be Happy Gilmore, which I think most people who know me would be surprised to find out. I watch this at least once a month and sometimes more, I can quote from it liberally and extensively. My favorite scenes are definitely the ones with Ben Stiller as a nursing home orderly. It makes me laugh every time.
Aside from that, I like The Italian Job, Dumb and Dumber, and Back to the Future. I must say that getting rid of satellite and the three-at-a-time plan from Netflix have cut into the time I have to re-watch movies: I could have made a much more extensive list two years ago, for example.