Here is a head that I was working on for fun and for learning. I tried to start out with a very simple mesh (made in Maya) and build it up to something very detailed. Here are the results:
This model was taken to subdivision level 5 and the rest was detailed with a 4096 X 2048 black and white map using the bump viewer shader.
I wanted to give my base mesh away to the community. I'm hoping someone else out there will take it and make something cool.
Base head OBJ (FREE DOWNLOAD)