Wild Card Divisional Conference SuperBowl
Seed   Overall     AFC     NFC     Overall     AFC     NFC     Overall     AFC     NFC     Overall     AFC     NFC  
No. 1 - - - - - - - - - 27 - 7 10 - 7 17 - 0 17 - 10 6 - 4 11 - 6 8 - 9 2 - 4 6 - 5
No. 2 - - - - - - - - - 25 - 7 13 - 3 12 - 4 10 - 17 5 - 9 5 - 8 5 - 5 2 - 3 3 - 2
No. 3 23 - 11 15 - 2 8 - 9 5 - 18 2 - 13 3 - 5 1 - 4 0 - 2 1 - 2 0 - 1   -   0 - 1
No. 4 24 - 10 12 - 5 12 - 5 5 - 19 5 - 6 0 - 13 5 - 0 5 - 0   -   3 - 2 3 - 2   -  
No. 5 10 - 22 5 - 11 5 - 11 3 - 6 2 - 3 1 - 3 0 - 3 0 - 2 0 - 1 0 - 0   -     -  
No. 6 5 - 29 2 - 15 3 - 14 1 - 10 1 - 1 0 - 9 1 - 0 1 - 0   -   1 - 0 1 - 0   -  
68% 3   5 31% 22% 3   1 79% 20% 3   1 63% 0% 3   1 47%
71% 4   6 15% 21% 4   2 78% 100% 4   2 37% 60% 4   2 50%
69% 3,4 5,6 23% 21% 3,4 1,2 79% 60% 3,4 1,2 50% 50% 3,4 1,2 48%
Text Box: Over the last 17 YEARS ...
The NFC # 1 seed has never lost in the Divisional Playoffs 
The NFC # 4 seed has never won in the Divisional Playoffs, while the AFC #4 is a perfect 5 for 5 in Conference Championships. 
There are only two AFC # 3 seed to lose Wild Card weekend:Seattle (to Miami) in 2000, and Cincinnati (to Pittsburgh) in 2005-06 playoffs. 
The # 4 seeds from both conferences are 24-10 in the first round, 5-19 in the 2nd. 
No # 5 seed in either conference has never won a conference championship, only 3  made it there.
2005 Pittsburgh Steelers became the first #6 seed to win in the Divisional Round. They went on to win the Conference Round and Superbowl, being the first team to achieve any of those feats. They broke many rules in their 2006 (2005 season) playoff run. 
The # 1 and # 2 seeds have met for the NFC Championship ten times, with the No. 1 seed winning six of those meetings (#1 is 6-4 vs #2)
The # 1 and # 2 seeds have met for the AFC Championship six times, with the No. 1 seed winning three of those meetings (#1 is 3-3 vs #2)
The NFC Super Bowl representative was always the # 1 or 2 seed until 2003-04 #3 Carolina broke in.
The NFC # 1 seed had never lost in the Super Bowl until Baltimore defeated the New York Giants in SB XXXV (2001), and has since lost several times as the AFC has grown stronger. 
The AFC # 2 seed had never won the Super Bowl until New England beat St. Louis in SB XXXVI (2002)
1 # 3 seed (Carolina XXXVIII runner up) has made the Super Bowl, and FIVE AFC No. 4 seeds have, including Super Bowl XXXII champion Denver, the 2000 XXXV champion Ravens

There have been 20 wild-card games in which the teams were divisional opponents who faced each other twice during the season. In twelve of those cases, the franchises split the regular-season series. Eight times, one team had swept the season series, and five of those teams went on to win the third matchup, pretty much debunking the popular but dumb notion that it is next to impossible to defeat a team three times in the same season. Most recently, St.Louis completed the trifecta vs. Seattle in the 2004-05 playoffs. Other recent divisional rival playoff results: 
2006: NE vs NYJ: Split season series, Pats won at home in playoffs. 
2006: PHI vs NYG: Split season, Eagles won at home in playoffs. 
2005: PIT vs CIN: Split season, Steelers won on road in playoffs. 

<UPDATED TO INCLUDE 2005-06 PLAYOFFS>
As of year 2002-03, the 3 seed in the chart historically is equivalent to the newer 3 or 4 in the playoffs, since 3 and 4 are both division champions now whereas only 3 was before. 
The 5 seed is now more similar to the 4 seed (top wild card).