I'll have to go with The Beatles, but really how can you compare Michael Jackson and The Beatles?
Arguably the greatest pop singer of all time and the greatest rock band of all time, but they're really not all that similar, unless you count Jackson owning the rights to the Lennon/McCartney collection (did he end up selling those while he was on trial last time?).
If you do want to compare them, though, take a look at just their singles. MJ had 18 number one singles and The Beatles had 27. Jackson's number ones were recorded between 1978 and 2003, The Beatles' number ones were recorded between 1962 and 1970. 25 years vs eight years, who had the bigger influence?