I think the best match up, as far as hype and the potential for a great game, would be Packers vs Patriots. Tom Brady and the undefeated patriots put their title on the line against the leagues only 3 time MVP, Brett Favre, in possibly his last game. It would be a great storybook finish for Favre to take one of the NFL's youngest teams and win it all against possibly the greatest team to ever play the game... Or even for the greatest team of all time to defeat the old gunslinger, in an "out with the old, in with the new" type of mentality... It would definitely be better then a Patriots vs Cowboys rematch...
Of course, you can never count the Colts out, seeing as they are as solid as ever, hungry to be considered underdogs even though they are the defending super bowl champs... This certainly will be a year to remember....