I was going to describe Kansas as the Hitler of classic rock, but then I remembered Uriah Heep.
Some 60's and 70's artists I'd recommend:
Brian Eno, Fela Kuti, King Crimson, Magma, Van Morrison, Can, Yes, XTC, Gentle Giant, The Kinks, The Zombies, Van Der Graaf Generator, Genesis, Samla Mammas Manna, Suicide, Keith Tippett, Sparks, Curved Air, The Clash, Talking Heads, Phil Ochs, Love, Hatfield and the North, The Beach Boys, Stevie Wonder, Roxy Music, Television