I moonlight as a DJ
(not as glamorous a gig as one would think!)...and we were just talking about this last weekend...
Theres many ways of measuring it:
Albums (CD) sales
Number of Top 10 singles
Number of Charted singles
Number of Number 1 singles
Overall time spent in airplay charts (Billboard/Cashbox)
Concert tickets sales/attendance
The Beatles are generally regarded as leaders in most categories except in some album sales categories. The Rolling Stones are a close second. Pink Floyd right behind...but again, there are SO many ways to slice it.
Before Jerry died...the Dead were on their way to some concert attendance record, while the Stones I believe currently lead in lifetime ticket sales...with upstarts U2
and Aerosmith close behind.
Our discussion was if U2
, Aerosmith or a future band would ever equal the mass popularity of the Fab Four...so far the jury says no.