The controller to be used in the Next Xbox, or 720 if you will, is apparently very similar to the controllers used by the Xbox 360. Other than some minor tweaks, it appears that Microsoft has decided that it is hard to improve on a good thing.
Reports claim the controller has the same two analog sticks, same D-pad position, same triggers, same bumpers, and, of course, the center power button. It is difficult to say if the buttons have been improved at all; but it is said to be bit smaller in overall physical size, with attention given to refining the contours and shape of the controller. Still, it is said to be quite similar.
Read more here.