Samuel Barber's 'Adagio For Strings' (not some crappy remix)
http://www.youtube.com/watch?v=lV3SHBFyDZM
in my mind, the most beautiful and heartfelt piece of music ever written. You simply cannot imagine a movement like this without it coming from the heart. the saddest piece of music. this video does it no justice. you really need to hear it live to feel the pain and heartbreak in there.