The best musician of all time is often subjective, but notable candidates include The Beatles, known for their profound influence and enduring popularity, or Michael Jackson, celebrated for his impact on pop music and iconic performances. However, other legends like Elvis Presley, Beethoven, and Miles Davis also have strong claims based on their unique contributions.

The question's ambiguity stems from the lack of specific criteria. To make it more objective, one could define criteria such as sales figures, awards, innovation, influence, or technical skill. For instance, evaluating based on album sales would lean towards artists like The Beatles or Michael Jackson, while innovation might highlight figures like Jimi Hendrix or Miles Davis. Establishing clear criteria would provide a more defensible answer.