The Aperture's main use it to allow more or less light through the lens.
The consequence of this however is that the depth-of-field is effected, which is a useful thing in some situations, of course if both were some how to be controlled separately it would be much more flexible.
I personally would use full manual mode to control the shadow detail and any other detail since it is then up to me, not the camera, in which aperture and shutter speed I choose for a desired effect.
With the High ISO Noise being brought down year on year and Higher ISO levels appearing, it may be that soon we can use F/16 in a dim lit room at 1/60 of a second @ ISO 256,000 or something (which i think the D3 does...?) if we want everyone in the room in focus!
Canon EOS 5DmkII + BG-E6 + Canon EOS 40D + BG-E2N + Canon EOS 33
Canon 17-40 F/4L
USM + Canon 24-70 F/2.8L
USM + Canon 28mm F/1.8 USM + Canon 70-200 F/2.8L
USM IS + Canon 85mm F/1.8 USM
Canon Speedlite 580EX II + Canon Speedlite 540EZ + 2 x Nikon SB-80DX
Cactus V2s Wireless Trigger - 5 x
Cactus V2s Wireless Reciever