Who is your favourite composer?
My favourite composer at the moment is Koichi Sugiyama, the composer who is famed for composing the music to the Dragon Quest games. He has been frequently called "The Father of VideoGame Music" and he deserves this title. Even within the tiny limits of the NES soundchip, he was able to compose wonderful works that became masterpieces when he orchestrated them. His main musical influences are that of J.S. Bach and Handel, and he composes at least one work per soundtrack that is in their style, which sounds remarkably authentic. There are a few fugues across his huge musical opus, if you search hard enough. He is also known as a wonderful orchestrator too, as shown by his DQ Symphonic Suites and the outstanding Orchestral Game Concert Series. If you want to start listening to VGM, the OGCs are a great place to start.
As for a Classical composer, I can't really say at the mo because I've only been listening to piano music recently. I'll say Ravel for the moment.