the most popular band in teh world (The Beatles) were way less commercialized than any band on a major label today; just because the record labels weren't out ONLY to make a buck. They were owned not by corporations, but by music lovers.
I agree with LZ being overrated, but The Who is really underrated. They were the best hard rock band of the time (assuming Sabbath is in the Metal genre). The Stones are overrated, but were nevertheless a great band. Sympathy for The Devil remains one of the best rock songs ever.
And this thread has gone this long without anyone mentioning Chicago? for Shame.