The average Gears of War character was about 8k-10k, then of course they had all sorts of crazy texturing techniques on them to make them look as brilliant as they do. For the average game, about 4k is the average for a humanoid
As hessiess said, you cant mess up the shape of a human because quite simply, everyone knows what a human looks like! The proportions have to be -perfect- in order to make the model be a believable human to a viewer. So... strict use of reference images and lots of studying! For animation, knowing the muscle structure of a human (
especially for facial animations) will help BUCKETLOADS. I thought those biology classes were completely useless, until we started animating in my 3D classes at college. Knowing muscles helps astronomically!