The composer, George Gershwin, who died at the age of 38 of a brain tumor... possibly one that could have been treated, even in 1937, if only it had been diagnosed in time. He died long before I was born, but I love his music so much that I feel a real sense of personal loss about all the music he might have composed, if only he had lived longer. He left the world with hundreds of marvelous songs, the great opera Porgy and Bess, and a handful of long-form orchestral works (Rhapsody in Blue, An American in Paris, Concerto in F). 

I know some people would say the same thing about Mozart, who died at 35, but honestly, if I could only resurrect one, it would be Gershwin.

Johann Sebastian Bach, for my greed in hearing more of his music.

Amy Winehouse, for letting her live a complete life.

(Did you say just one?
Ok: Amy W. will just come back to our little planet,
and not be a singer anymore,  if she agrees on that,
would that work for you?)

By the way, I believe you asked us as you have
the power to fulfill our wishes.
When will you start?