I just finished watching Airplane for probably the 50th time, and it never gets old! Never! Even watching it on AMC with commercials every 10 minutes was more than do-able. If I ever really hit rock bottom, I'd make a point to watch the movie all day long. It would set me back on the right path again.
Since I haven't quite hit bottom yet, I'm spending my time watching Bon Voyage starring Gérard Depardieu. There's nothing better than subtitled films set in France during WWII involving heavy water (D2O.) Deuterium is such a blockbuster isotope; I don't think its Hollywood potential has been adequately explored.