Hurm. I don't know which music there will be in the future, I'd like to hear it but well.. I can't
. So, for me are:
Classical composers as Beethoven, Strauss, Vivaldi, Mozart, Chopin and others.
Bob Dylan because of his lyrics and maybe John Lennon too (just for Imagine).
Billie Holyday, Edith Piaf, Aretha Franklin, Freddy Mercury for the amazingness of their voices. But I should include Mariah Carey, Barbra Streidsan and Celine Dion as well. Although I'm not a big fan of their music.
Deep Purple, Led Zeppelin and Pink Floyd because they're true legends and their music is really inspirational.
But we can't forget huge and popular artists such as The Beatles, Rolling Stones, Elvis Presley, Radiohead, The Beach Boys, and many others.
I would include Lady GaGa and Madonna as well though. They're maybe not so talented (even if I heard some songs of Lady Gaga, before her career and she has a great voice) but they know how to catch people's attention and they're great performers.