Painters -
Vermeer and
van Gogh are the two I enjoy the most. But, I don't know enough about the subject of painting to have a very informed opinion.
Composers - I have played the cello for 20 years now, so there are many. But my favorites would have to be:
Bach(for his six suites for cello)
Mussorgsky(for
The Great Gates of Kiev)
Prokofiev(for some unbelievably challenging cello pieces)
Liszt(for his pure fucking genius and his piano compositions)
Beethoven(for his 9th symphony)
Tchaikovsky(for his violin concerto and his piano concerto)
Haydn(for his two cello concertos)
Mozart(Although he is the trendy one that everyone likes, and certainly not the best despite his popularity, I do rather enjoy some of his operas. Namely
The Marriage of Figaro. His Requiem is also fantastic, specifically the Sanctus.)
Handel(for
The Messiah)
That's a good start.
I could also name some overrated composers that I hate, but why be so negative and mention a charlatan like
Aaron Copeland when it's not necessary.