I think the first band that I enjoyed that's stlll considered 'metal' is Black Sabbath,
in particular, this album:
Back when I was a young man, a lot of the bands that were called "heavy metal"
are now considered "hard rock', since the ultra-hard stuff didn't exist yet.
The music my friends and I were into were all guitar-heavy groups--Rush, Aerosmith,
Led Zeppelin, Ted Nugent, AC/DC, Frank Zappa, Van Halen, etc.--and later, most of
the NWOBHM groups (Def Leppard, Diamond Head, Iron Maiden).
Speaking of Iron Maiden, I still love those first two albums with Paul DiAnno!