With regard to the question in the last post from Toady:"Is there some planing on a better undead system? I mean, it gets tiring to fight animated hair, hides and such, so what I'm really asking is that if you are thinking into a more "classical" representation of undead, where the pieces that fall don't stay alive and ultimately only smashing the head or decapitation would stop the zombies."
I have to point out, the way it is in DF is the classical representation of undead. With the exception of hair, all stories of undead I heard created before the very recent pop culture versions (last couple of decades) had undead that were animated by magic, and were virtually indestructible. Mostly there was some kind of logic, ie. they had to have a muscle in the body part to move, but generally animated body parts were the norm. The 'cut off the head or destroy the brain' style undead comes from the much more modern concept of virus outbreak zombies where some kind of vague biological explanation is expected. I miss the old style zombies and am glad that they still exist here if nowhere else, although I don't have a problem with it being scaled back a bit so that some of the more ridiculous cases are reduced.