As few as possible. You can normally get a fairly rounded looking cylinder for a body part with 6 or 8 sides using smoothing. Most of your polys will end up in the head, increase complexity where you need it only like the nose, ears and eyes and mouth. The easiest way to do that is by using extrusions. It's tough to get a blinking, talking character with under 1000 vertices, at least it is for me. MMORPG's are a huge amount of work and very few individuals ever finish one.