60's CREAM
70's Sabbath or Purple (Zep were rock certainly, but hard rock?)
80's Metallica
90's Alice is close, but nothing really stands out and equals the above
20"s Hard rock is dead. Foo Fighters are rock, not hard rock. Nothing much out there and nothing interesting.
The interesting point from a dinosaurs perspective, mine, is that really good acts bust through the controlled music industry. While there are absolutely a few very good bands out there, they don't come at you like a Cream, Zep, Hendrix, Purple, Who, Sabbath did. Considering their age and the lack of technology as we know it today, they were rather special.
Remember what wasn't invented yet:
Guitar Stands
Long Guitar chords
Foldback Monitors
Bass amps that were able to be heard or sound clear
Road cases
Decent Mic's
Sound Boards
Lighting
"Clothes"
FOH sound mixing
Guitar tuners - a very big advance
EQ
And, we still got more gigs and more chics then too.
Long Live the baby boomers, Rock Music was our time.........