My favourite guys? Well, maybe too many to mention. As you say, it was a great era for fight fans.
Obviously in the heavyweight division Ali was the man but I also had a lot of respect for the guy who had to follow him, Larry Holmes. Holmes tends to be dismissed because he wasn't Ali; he didn't have his personality or pizazz but he was an excellent boxer with a punishing jab and a terrific chin and powers of recuperation. Like in any sport, you achieve greatness by the opponents you beat and by that margin Holmes deserves real respect. Ali had Frazier, Foreman, Norton, Liston et al. But Larry Holmes was equally blessed in what I think may have been the heavyweight division's toughest era. Ron Lyle, Mike Weaver, Earnie Shavers as well as the aforementioned Ken Norton makes for a pretty impressive list of power punchers who Holmes dispatched; sometimes after taking their best shots and getting off the canvas in the process.
But any fight fan will tell you that the best stuff is alweays to be found in the lighter divisions and there were some magnificent smaller guys during the 70s and 80s. Particularly middle and welterweights. In particular that time in the early to mid 80s when Ray Leonard, Roberto Duran, Tommy Hearns and Marvin Hagler were all around at the same time. They had some monstrous encounters. Amongst others I'd list Alexis Arguello, Wilfredo Benitez, Salvador Sanchez, Julio César Chávez, Carlos Monzon, Esteban de Jesus...like I said, too many really.
I also believe that despite the money it has raised for the purses of fighters pay-per-view was the worst thing that ever happened to boxing from a fight fan's perspective. It used to be that all the big fights were shown, if maybe delayed, on regular network TV. But with the introduction of satelite and pay per view coverage the average schmo can't even see the highlights without forking out serious moolah. That, for a working class sport, means that fighters who should have become household names are only known about by hardened fans and I, for one, couldn't judge how modern day fighters comparte to their earlier counterparts because I never get to see them in action.