How about them Steelers!

Before it was dubbed the "Superbowl" (for comercialized reasons/hype etc) it was known as the NFL Championship game. As far as Championships go there are some teams that have more than Pittsburgh. Green Bay(12), Chicago(9) Cleveland( I think has 8, but none in the "Superbowl era") just to name some, the Steelers getting six in the last 40 plus years is really very impressive though because they were a fairly dismal franchise for decades before the 70's).