Oops...  Much thanks to 'MetalFanDownUnder' for reminding me of "Deep Purple" -- 1st album I ever bought...

But do you classify DP as 'metal'?  More like 'hard rock', wouldn't you say?  I think Priest were the first real 'metal' band.  I read somewhere in an interview that either Halford or Downing response to someone's opinion that, "Ozzy is heavy, and JP is metal"  was, "I like that."