In addition to the list - my favorites:
Alan Parsons
Ambrosia
Camel
Eloy
Focus
Gentle Giant
Iron Butterfly
Journey (before Steve Perry)
Jean-Luc Ponty
Mahogany Rush
Mastermind
Moody Blues
Nektar
Procol Harum
Renaissance
Spirit
Strawbs
Supertramp
Traffic
Triumvirat
Uriah Heep
Wishbone Ash
The Who
Most I don't know though...ha!!