Jason--In all reality, its not possible to swing on one plane, simply not possible...I don't care what Jim Hardy says. There are always 2 planes in a golf swing, the plane from the ball up the shaft and the plane from the ball up over the shoulders (i.e. Ben Hogan's book) There are always those 2 planes.
--People today have different swings though, Sergio, Furyk, Dimarco, Craig Parry, Daly. Those swings are as different as anything seen before. And in those cases, they are very markedly different.