Since the capacity to store historical artifacts is different now than at any other point in history, virtually anyone will be 'remembered' depending upon the interests of the seeker.
However, those folks who are known by most -- as in, still part of popoular culture 5 centuries hence (as Beethoven, DaVinci, Columbus, Galileo, etc. are today), depends so much upon how world culture evolves. It may be that the folks who we see today as so influential, such difference makers in this century, may be forgotten based on the twists and turns of human values moving forward. We still see DaVinci and Beethoven as having an influence on today's world, and therefore they are remembered. If I had to guess, I'd say Beethoven is more likely to be remembered in 500 years than any of the aforementioned musicians. I'd like to think that The Beatles and Elvis would be remembered, but once everyone is dead who was alive while they were in their heyday, the passion of keeping their memories alive will be mitigated -- only the historians will care -- unless, of course, their music stands the test of time. My guess is that only those with a passion for musical history will eventually know Louis Armstrong, The Beatles, Elvis, Dylan -- while the mainstream folks will only know their current artists along with with classical geniuses. Just think today about how great a musical artist like Gershwin (for instance) was -- and he is already unheard of by most folks under 40.
Helen Keller is a historical icon, but will be forgotten to modern culture as soon as those of us who remember her die off.
Einstein will matter in the way Galileo, Copernicus, etc. matter as he'll be seen as a father of important work in the history of humankind.
Thomas Edison, Alexander G. Bell, Neil Armstrong and Charles Lindbergh might make the list as answers to trivia questions.