Arthur C. Clarke died at age 90

Science-fiction author Arthur C. Clarke is one of the people that has defined me as a person and who's books provided both comfort and excitement during my childhood and adolescence. He is mostly known for the movie adaptation of 2001: A Space Odyssey although I liked the Rama series more. He also invented the concept of a geo synchronous satellite. 
He has lived a full life and I don't believe in artificially prolonging living above a certain threshold (he was suffering for 13 years now), so I am just happy to have known about him rather than sad for his death.

More details at this BBC News article and this Wikipedia entry.