I think Smoke On The Water coming into the house on 45 was a major sea change. For the next few years I ate up Deep Purple, Zeppelin, Tull, Aerosmith, etc. For odd hard rock I have a fondness for What You Got by Duke and The Drivers. Great rocking tune. I tended to stay on that early 70s line of not obviously metal, but post garage-y hard rock. That could even have been bluesy stuff like J Geils.
I had some interest in that late 70s California guitar stuff like Van Halen, and Yesterday And Today, but when I first heard the Sex Pistols that stuff just got shut off for a long time.