Subjective but I think #1 has to be Metallica with everyone else tied for 2nd. Those of us old enough probably remember when Metallica hit and they were definitely different from everything else that was out there at the time. They kind of took it to that next level.
40 years of Metallica albums and touring speaks for itself. They are still going strong today even at 60 years old (some of them). I mean how many fans have been at their shows in total and they still sellout.