This post reminded me of a story I heard about AC/DC.
Apparently Angus and Malcolm Young have an older brother who was a successful pianist. Malcolm and or Angus would write a guitar riff for the band, and before fleshing it out in to a song they would take it to their older brother who would play it on the piano. If it still sounded all hardcore and badass coming from the piano they would proceed with it, if not they threw it out. I have no idea if any or all of this is true, but I love the idea behind it.