Nodame Cantabile (for obvious reasons) - girls and dudes Sakamichi no Apollon - dude Piano no Mori (even more obvious reasons) - girls and dudes Time of Eve - dude Kobato - dude Tari Tari - girls
How current? The Violinist of Hameln had a guy who uses a piano as a weapon. (He played the overture from Swan Lake on it and a huge swan made out of water would fly out of his piano and attack people.) He also carried said piano slung on his back.