NFL.com article. Worth a read as it is based around the idea that the league is moving away from high powered offenses and instead towards simplified, talent based defenses. Anyway, Panthers:
1) Carolina Panthers
The Panthers finished the regular season hot on the Seahawks' heels in two important defensive statistical categories, ranking just behind league-leading Seattle in points and yards allowed (Carolina yielded just 15.1 and 301.2 per game, respectively). Their defense also played a key role in their run to the NFC South title; after starting slowly, Carolina won 11 of its last 12 contests in 2013, limiting the opponent in each win to 20 points or fewer.