The first thing that really stood out when looking at the Packers/Dallas matchup is each team's pass defense.
Dallas' pass defense has arguably played well this season, but they have played against a lot of bad pass offenses. They did host New England, but QB Tom Brady tore them apart. The 2nd best pass offense they've probably faced is the NY Giants. I know QB Eli Manning's QB rating is hovering around 75 and he just had a 4 INT (3 returned for a TD) game against Minnesota, but if it's not them then it's either Washington or Philadelphia. The other teams they've faced (Miami, Chicago, St. Louis, Buffalo, Minnesota, NY Jets) all are bad to awful throwing the ball.
The same criticism could be lobbed at the Packers schedule. The best pass offense the Packers have faced is probably Denver, and QB Jay Cutler had a pretty good game. Also, the Packers haven't gone up against any team with a great wide receiver, so who knows how they will do against WR Terrell Owens. Plus the Packers have been torched by tight ends this season, and TE Jason Witten is one of the best in the league.
This game will be a real test whether either team's pass defense can shut down a top flight pass offense.