Maybe you should have said "favorite" not best. These posts do not seem to be objective. If we are talking about someone alive, perhaps Quincy Jones should be on top of that list. He is the most accomplished musician I can think of, with significant contributions in every field, performance, composition, arranging, conducting, producing, publishing,executive administration and mentoring younger musicians.
Best musician in the world?
A question posed in another thread, in my view, although musicianship is hardly a sport to be measured as such, the most universally prodigious musician is probably Shawn Lane. He is definitely the world's most phenomenal/inimitable electric guitarist. And he is a world-class pianist and saxaphonist as well.