Ockham, for reference
Personally, I'd either take the end of the arm or one of the covers that hid all that extrusion and belting from the world. Simply because they're the sexiest parts 1293's put on a robot. Close second and third goes to the aluminum we used to mount electronics and the pulley housing, which takes the place of the kitbot top plate in that picture.
(Yes, I just called a couple of parts off our robot sexy. Yes, I am a geek.)