Regarding high polygon models. Poser, in my opinion, has a very good "smooth at render time" algorithm. Try rendering Posette in Poser 4 then again in Poser 8 and you'll see the difference. The idea being that you do not need very high polygon models in Poser. If you need intricate surface detail then look to apply those with textures, bump and displacement maps.

More recently I've been using ZBrush which does indeed handle very large polygon models. What I've been doing is to import my "regular" Poser model into ZBrush, subdivide to get approx one million polys then work on that to get the surface detail. Wrinkles in cloth, veins in flesh etc. I then export out the alpha map and apply that as a displacement map to my original model.