AFC -(tie) Kansas City - they come back to the playoff hunt now that their entire team isn't injured anymore
Buffalo - Fred Jackson is very underrated - great RB tandem, good passing game, and an improved defense - and 4 wins against the Jets and Miami could propel them.
NFC - Seattle - their defense is legit. Their run game is legit. If Russell Wilson is half as good as people believe, this team could challenge San Fran for the division and make some noise.
P.S. - I would also put Chicago, but I wouldn't consider them a big "surprise" team - though I definitely see them making the playoffs.