I've had this preference for a few years now. I don't like moderately long "Emo length" hair. Around shoulder length (and especially longer) hair looks better to me. When paired with a rocker kind of look, it's even better. I don't like a complete rocker stereotype though. Niceness is a must. Whenever I imagine the perfect guy (physically), he has long hair. I would not avoid a good guy due to hair length, but long hair is definitely a bonus to me.