On the Nikon, you have another option apart from the shutter priority mode - Program mode, you can rotate the command dial to all the various shutter speed and aperture combinations that give the same exposure.
Example, if F8 and 1/250 make it correctly exposed, then rotating the dial one way will take you to F5.6 and 1/500 or rotate it in the other direction for F11 and 1/125.
Basically it seems to do away with the need for the aperture priority or shutter priority mode. Or am I missing something