The little bag that came with the Campag brake levers had black cable housing with "Campagnolo" written on it, so that's what I use. Have never thought about cable housing color, figure that's something in the wives'/gf's purview. "Honey, what color housing should I get?" "Oh, I wouldn't be able to live without the heliotrope!"
I do remember somewhere back in the long obscure past, though, that my first really good bike, a Peugeot PX-10, came with this cheap French white cable housing attached to some really grotty Mafac Racer brakes. If you pulled real hard, you could see the plastic housing shrivel over the top of the metal housing wrap. So I guess I have always associated white cable housing with "cheap" and "ineffective."
Sorry!
L.