well, I also got confused by the question, and the first name in my mind was also Niccolo Paganini.
and of course, "the best" is very subjective. Like choosing a Miss World. How do you choose one, when all the finalists are beautiful?
Hm, I would like to share with you here something that bothers me. Here in Vienna, in the Philharmonic orchesta, they take only white male musicians. Lately they took some women, because there was too much pressure to do so (I suspect they would have never done it out of free will). But I read an interview with a former director of the orchestra, and he sais, yes we take only white men to play music, composed by white men, and this is right so. There was a case when a japanese musician won a competition behind the curtain, but they refused to take him. I think this is bullsh.. But I am not a musician myself, so may be...i am wrong?