Pre Intro. Kind of like a pre-meeting. So, what are the rules?
I am not including anything that is not metal (or at least aluminum). So no Springsteen, Buffett, Hornsby, Pink Floyd, Genesis, Joe Jackson, Phish or Moby. All of which have albums that are among my favorite 250 of all time.
So, I will go with the "I can't define it, but I know it when I see it." definition.