Now the best part - high poly sculpting in Zbrush.
That's the part I like the most, especially now when Zbrush 3 is available.
After Unwrapping in 3ds max I've exported the models to obj formats and then import them in ZBrush and start sculpting. Sometimes I use muscle pics as a references photos and some works from other cg artists as well, especially those done in zbrush.
You probably heard that million of times but I will say it one more time - be patient while sculpting your models, do not model details before the main shape of the muscles is not done. If you in a hurry your model will loose on quality.
Although the zbrush have the power to manage millions of polys I usually do not model lots of details like a skin facture, I just use bump maps that are created from my color map. In practice I connect the bump maps with baked normal maps.
You can read more about this technique in my normal maps tutorial on the Evermotion site.
Below you can see some of the high poly models, I know that they are not as good as you can see at Zbrush forums but for the game art purpose it will do.