It seems as though the most needed prosthetics are hands. Which do you guys think are the best open source models out there for this cause?

I am leaning toward:
The Cyborg Beast - http://www.thingiverse.com/thing:261462 (And this remix - http://www.thingiverse.com/thing:308124)
The RoboHand - http://www.thingiverse.com/thing:92937
Flexy Hand - http://www.thingiverse.com/thing:242639 (although no prosthetics have been made yet, this has so much potential if someone could make it work).