My top 16. 10 was too limiting. :tongue:

Gustav Mahler
Igor Stravinski
Dimitri Shostakovich
Jean Sibelius
Béla Bartók/Aaron Copeland
Sergey Prokofiev
Arnold Schoenberg
Morton Feldman
Alban Berg
Charles Ives
Karlheinz Stockhausen
Arvo Pärt
John Cage
Phillip Glass
Iannis Xenakis