It was Joe Frazier for me. But I was just a young fella, I only know this from reading about it later. Having watched him on videos, I am very happy such a great champion held the title when I was born. Joe is one of my all time favourite fighters.
Joe Frazier but I don't know off the top of my head if he had unified yet. Edit: He had not. Of course a lot of people still felt Ali was the champion as he had not lost his title in the ring.