Get two or more guitarists get together, and the discussion will eventually wander to the question: Who is the best guitarist?
With so many players to choose from, in so many different styles- let's face it, there never was, and never will be just one "best"; and after all, what we really mean by "the best" is "my favorite". Insisting on your favorite will only prolong an argument, not end it. It's a classic case of apples and oranges, or even fruit salad.
Don't get me wrong; it's good to have guitar heroes. It's good to have opinions about players. However, a better question to ask might be: WHY do I think that (fill-in-the-blank) is the best guitarist? When you answer that question, you actually begin to learn something…or teach something!
One of the reasons that guitarists look for "the best" is that we secretly want to BE the best. And even the best players have other players who they look up to. Andres Segovia, the grand master of the classical guitar, had the inspiration of Gabriel Ruiz de Almodovar, of whom he said "I felt like kissing the hands of a man who could draw such beautiful sounds from the guitar"; and although he'd never met Tarrega, the maestro reverently referred to him as the man who "created the soul of the guitar".
So, here's the bottom line: aspire to be the best (at whatever you do), and remember that even the "best" players are trying to do the same thing.