It's all relative. You need to look at your target audince, i.e. who's going to be playing your game? Snake's mustache in MSG4 apparently has the same amount of polygons as a complete character from MSG3...

In the Unreal 3 technology demo, I noticed that most character models only used about 5,000 polygons. You don't need very many, because the real detail should come from normal maps/textures.