Years ago I created a website for local bands. I also liked to have a rating system and tried an emotion rating system (example: http://achterband.nl/sickboys_and_lowmen/white_buffalo).
I think for music and films this is more suitable than giving it a single number. And maybe this applies to other ratings as well.
(Translation of the emotions used: happy, relaxing, surprising, aggressive, sad, explosive)
(Translation of the emotions used: happy, relaxing, surprising, aggressive, sad, explosive)