Favorite movies of all time

I was recently asked to tell somebody on the spot what my Top 10 Movies Of ALL TIME EVAR!!! are, and I can't tell you how difficult a task that is. I can list maybe my top ten comedies or dramas or action flicks, but how do you compare Some Like It Hot to The Good, the Bad, and the Ugly? I am going to have to get back with you nonexistant readers on this. Perhaps I'll break the list up...