Well, I don't normally follow Cult Cinema, often times its classification confuses me and after that debacle, I usually find what's considered cult pretty appalling, or never understand the reasons why it's considered cult. A Clockwork Orange is one, absolutely terrific film, but whenever I hear it described as cult I have no idea what people are getting at, it jsut seems to be a get-out clause for those who struggle to have a worthwhile opinion. That, and I also don't like Donnie Darko, so perhaps I'm not the best judge on Cult Cinema.
However, there is one I'd like to see on that list. Chuck out Quadrophenia and The Warriors, what about The Wanderers? It does the gang thing better than The Warriors, and I prefer it's tale of confused youths to that of Quadrophenia (though I do like Quadrophenia). Memorable scenes, great music, distinct characters, consistently humourous, it's a highly enjoyable and fun film.