Clemenza is my favorite. He was dependable and loyal (and I'm thankful Richard Castellano chose not to appear in Part II because the thought of Clemenza turning rat is unimaginable).

He had a wonderful down-to-earth quality about himself... remember his "talk" with Michael in his basement (when teaching Mike about shooting Sollozzo), his teasing Mike about (then girlfriend) Kay, and his manner in which he stole the rug (with Vito). Remember, too, it was Clemenza whom Vito entrusted with bringing Mike back safely from Sicily.

He was capable at his job and he was funny, too. All in all, a great character.