Ali, Jordan, and Ruth were obvious in sports. Those guys smashed their respective sports and rearranged them to their liking.

Dylan's influence and fingerprints are all over "the" singer-songwriter, so there's no question he should be top 3. The Beatles are the same as they will probably never go away. Elvis is there for exposing America to it all and being a huge juggernaut.

Brando is simply amazing and his impact on the acting game goes without saying. Gregory Peck was simply magnificent in anything he touched, so I definitely give him his props, and De Niro as the standard bearer for these last few decades.