The New York Giants are the reigning Super Bowl champions, but quarterback Eli Manning knows from first-hand experience that his National Football League team can't afford to be complacent.
"We know we've got to improve," said Manning, whose team sneaked into the post-season last year then went all the way.
"We were 9-7 last year in the regular season. That's not good enough. We've got to have that urgency, that consistency, throughout the whole season, and play our best football for the 16 regular-season games."
It's the opposite story for National Football Conference (NFC) rivals Green Bay, who powered to a 15-1 regular season then fell to the Giants in their playoff opener.
"We went through a great regular season, winning 15 games and doing a lot of things that hadn't happened here in Green Bay before, and got knocked out in the first round," said Packers quarterback Aaron Rodgers, the regular season Most Valuable Player.
"It makes you realize the only thing that matters is winning championships, and you have to win some playoff games to get there."
Manning and the Giants made the most of their post-season chance, beating favoured New England Patriots for the Super Bowl title.
New England quarterback Tom Brady matched a Super Bowl record with his fifth career start last season, and will be a strong choice to challenge again to join boyhood idol Joe Montana and Terry Bradshaw with a record four Super Bowl wins.
With Brady at the helm, the Patriots remain the class of the American Football Conference (AFC).
Defence remains the cornerstone of the Pittsburgh Steelers and they again promise to be be a smothering unit.
On offense, Ben Roethlisberger is another quarterback seeking a Super Bowl return and if he clicks with new offensive co-ordinator Todd Haley the Steelers could add an explosive offense to their defensive strength.
More mystery surrounds another future Hall of Fame quarterback, Peyton Manning, the four-time NFL Most Valuable Player who led Indianapolis to a Super Bowl crown in 2007.
He will make his long awaited return from injury at the helm of the Denver Broncos and his arrival makes the Broncos instant contenders in the AFC West, but the 36-year-old missed all of the 2011 season after a fourth neck surgery.
Stepping into Manning's shoes in Indianapolis will be top draft pick Andrew Luck, the college star who is one of five rookie quarterbacks expected to start in week one of the season - an unusually high number in a league where the key offensive players are thought to need more seasoning to be ready to lead teams.
The Washington Redskins are putting their faith in Heisman Trophy-winning Robert Griffin III, Miami are going with Ryan Tannehill, Cleveland will start rookie Brandon Weeden under centre and Seattle have tabbed Russell Wilson.
The Giants will open 2012 on Thursday (12pm SkySport ESPN) hosting NFC East rivals the Dallas Cowboys.
Other NFC teams aiming to knock the Giants off their perch include the Philadelphia Eagles, who will be hoping quarterback Michael Vick can stay healthy, and Green Bay's rivals in the NFC North, Chicago and Detroit.
New Orleans own a wealth of talent in the NFC South, but will be handicapped by the sanctions handed down by the league for a pay-to-injure "bounty" scheme.
Head coach Sean Payton was banned for the entire season over the affair and replacement Joe Vitt won't be able to take over until he serves his own six-game ban to start 2012.
The turmoil couldn't have come at a worse time for the Saints, who are hoping quarterback Drew Brees will still be able to lead them to a Super Bowl scheduled for their own Superdome.
The bounty scandal wasn't the only source of turmoil this off-season, and 2012 will open with replacement referees in charge of officiating as the league's contract dispute with their referees rumbles on.