Science will preserve many names so Einstein's will remain well known like Newton remains well known. The hair only helps. Names like Heisenberg, Watson, Curie, Oppenheimer and LemaƮtre will be remembered, but probably only by scientists. Scientists whose names are preserved in the periodic table or in units of measurement have an advantage.
Hitler was a brilliant choice, and I definitely consider him the most likely political leader to be remembered. Churchill had so many great quotes that might keep him remembered. Kennedy is the most likely US President to be remembered because of the assassination and the resulting conspiracy theories. Stalin perhaps, but who knows what Russia will be by then. Mao.
Neil Armstrong is a great mention. I tend to think MLK will fade a bit as the concept of race changes fundamentally over the next 500 years. I don't expect there to be meaningful identity in the US based on skin tone 500 years from now.
I wonder what musicians would stand the test of time. If I had to put money on someone, it would be on the Beatles. Perhaps someone like Andrew Lloyd Webber would have staying power. I find it hard to imagine how today's movies will be considered in 500 years. I expect that technological changes will leave our movies seeming a bit quaint. Still, future centuries will have access to video records of the present that we do not have for 500 years ago.
Bill Gates has a chance to become a bigger icon. If his foundation is successful in its initiatives against malaria, aids, etc, I can see him being remembered far longer than past tycoons.
I am hesitant to include any athletes because sports will be far more international, and the records of a single league like the NBA or MLB will be far less significant.
Freud may be remembered, though much of his ideas will be disregarded as pre-scientific ideas of the mind.