WHAT HAVE I DONE TO DESERVE THIS? : Want to really impress your date this Valentine's Day? How about not> following Puff Daddy's lead. The be-docked one took time out from cultivating his image as more sinned against than sinning to arrange a treat for sweetheart Jennifer Lopez - a live seranade from Luther Vandross. Which raises the question - is that what these people really listen to when they're not working? And should Nicole Appleton be expecting a visit from Joe Longthorne sometime soon?