Not to stray too far from the thread -

This is an example of what I meant. The image on the left is what it looks like while I'm working on the low res. The image on the right, is the wires for both the high and low res mesh.  As you can see, I keep the basic form and look of the high res-Zbrush sculpt without the wasted polys.  To be honest, I could cut it down even more but I chose not too, for the sake of smoothness when rendering.