Cream was at the top of the heap. Following was Jethro Tull (e.g., Benefit, Stand Up), Jimi Hendrix and Led Zeppelin -- I still remember listening to their just released first album at a friend's house. There were lots of other great bands like the Animals, the Doors, Chicago, the Mahavishnu Orchestra, Osibisa and even softer rock groups (remember Windy?).
Later in life, during college, I discovered the Moody Blues and Pink Floyd. They'd been around in my earlier years but I never listened to them. Makes me wonder who's around now that I'm missing. Good thread. Thanks.