Ludwig van Beethoven
Hard to believe, but I’ve been playing classical piano for over 20 years. Seriously. One of my all-time favorites (cliche as it might be) is the first movement of Beethoven’s Moonlight Sonata. Ironically, I never got ahold of actual sheet music for this piece until much later, but man, it was all worth it. It, like many other classical compositions, have been used for a variety of purposes in film, television and video games, my favorite being the juxtaposition of this calm, quiet music amidst the horror and mayhem of a particularly violent scene (the hallway fight in Oldboy, for instance). Definitely something to chill out to while writing.