I saw this when I was a freshman in high school, and it prompted a totally weird adolescent phase in my life during which I dressed in faux-vintage 1920s outfits for several months and carved a Louise Brooks face into a pumpkin for Halloween.
Louise Brooks is like a beautiful alien. I've never seen an actress look so other-worldly in motion. Also, the scene with the headmistress practically orgasming while directing the girls to do calisthenics is probably one of the most successful combinations of humor and perversity I've seen in a film (whether or not that was intentional, I don't know).
Incredible how Louise Brooks looks innocent throughout the whole movie even during the sleaziest scenes. Incredible how some of the actors look so modern that they seem to have just popped out of a TV show. Incredible how the 104 minutes of the film pass so quickly while I have to look at the clock every 30 minutes or so when I watch a modern-day movie. Masterpiece.
Pabst combines an impressive 'joie de vivre' with acidic observation, only slightly diluting his message with a happy-ish ending which was imposed on the director by censors. Brooks is dazzling throughout with one scene in particular standing out: an almost serpentine dance with a bordello client which becomes a sexual experience more erotic than any overt 'act of love'.. I think I'll go for a cold shower now... ;)