Thanks folks.
Art, I use edge extrusion for almost all of my human-organic modeling. I learned head modeling using this excellent 3DS-based tutorial:
http://www.3dtotal.com/ffa/tutorials...farc/head1.asp
Of course, I don't follow this pattern exactly, as AC3D has a different toolset (plus the author of this tutorial is *much* more polygon-efficient than me, and his shapes flow much better than mine usually do), but this guide was invaluable in my learning. I'd also be lost without AC3D's edge extrusion features, and I've come to depend heavily on the Divide Loop plugin.
Of course, if you're into the box-extrusion method, that's a completely different subject...
