According to the NFL, the #1 greatest Championship game of all time is the “Ice Bowl”, 1967 Packers vs Cowboys:
http://www.nfl.com/videos/nfl-hq-videos/09000d5d815e2d74/Top-10-Championship-games
TOP 10 Championship Games of All Time
10 1992 Cowboys 30 49ers 20
9 1983 Redskins 24 49ers 21
8 1994 49ers 38 Cowboys 28
7 1998 Falcons 30 Vikings 27
6 1990 Giants 15 49ers 13
5 1987 Browns 38 Broncos 33
4 2005 Colts 38 Patriots 34
3 1986 Broncos 23 Browns 20
2 1981 49ers 28 Cowboys 27
1 1967 Packers 21 Cowboys 17
Top 10 Super Bowl Teams
Monte Burke and Matt Woolsey, 01.23.09, 07:30 PM EST
Cowboys top a list of the best Super Bowl-era teams. Since the first “World Championship Game” in 1967, the Cowboys have outpaced all other NFL franchises when it comes to full-season performance. Though the team is tied with the Steelers and the 49ers for the most Super Bowl wins* (five), it has the most Super Bowl appearances (eight), a record 29 playoff appearances (which means they’ve missed the playoffs only 14 times in the last 43 seasons) and the highest regular-season winning percentage during the Super Bowl era (0.606, besting the Miami Dolphins’ 0.579).
* This was written a year ago, 01-23-09.
I find it remarkable how few of these conference championship games have gone to overtime.