Metal is different things to different people.

My favourite Metal band is TOOL but I'd never consider them as 'Heavy metal' and they are even sometimes filed under 'rock'.

I don't think I could label Metallica as heavy metal - hair metal maybe ;) - I just can't take them seriously, especially after some kind of monster / St. Anger. - don't get me started on megadeth ;)

There are bands that I don't really get into but still have respect for - like Alice in chains or Judas Priest.

Motorhead do have more than one song right? If I head ace of spades in a tv show or movie one more time i think my head might just explode!