1972 Dophins, the only NFL team to ever to win the NFL Championship without losing a game all season. There can be no aurgument that any other team was better; '78 Steelers lost 2 games, '07 NE lost the big one (choke!), '85 Bears lost to Marino, '98 Broncos lost 2 games. Every team that won a championship tasted defeat except the '72 Dolphins. Sure the teams today under todays rules might beat those Dolphins but the fact remains, Miami 17-0!!!