The 9ers were good, and Joe Montana was one of the best. But Bart Starr and Lombardi were not only great, they defined greatness in the NFL.
And as for any given team, I think the Cowboys' 72 team, which had Packer great Forrest Gregg, Bears great Mike Ditka, Chargers great Lance Alworth, plus the usual stars (Lilly, Renfro, Staubach, Calvin Hill, Duane Thomas, Bob Hayes) was as great a team as there ever was, including the Miami Dolphins of the following year.