Paulie Walnuts for me.In fact I think he is the character that best illustrates your average mobster,as well as the whole Cosa Nostra,its fickle nature,as well as its decline.

He was once young,very tough,very strong and very feared.Now he is old,he retains some of the fierceness he had,but not all of it.He is street smart and sometimes cunning.At the same time he can be petty,narrow-minded,and set in his ways.He is sometimes shown to be very competent.Other times he is a barely functioning idiot,or at best a child.At times he shows fierce loyalty to Tony and the crew,other times he is disillusioned and sells him out.