The spawn of metal genres over the decades has led to much confusion,even among metalheads, about what metal is... Thrash, Speed, Death, Dark, there's more of them than you can shake a stick at!
But 'Heavy Metal' is where it started (obviously discounting Blues Rock, Hard Rock etc as predecessors

) so the question is, who in this day and age still fall squarely into the 'Heavy Metal' genre, and who's your favourite?
For me, as Number of the Beast was the first (vinyl) album I bought with my own money, it's got to be Maiden...