There's a neat tool at the Wall Street Journal for simulating brackets. Near as I can tell the results are pretty random.
In order to include the Ravens, I ranked the divisions by point differential.
AFC
1 Colts
2 Patriots
3 Ravens
4 Broncos
5 Jets
6 Steelers
NFC
1 Saints
2 Vikings
3 Eagles
4 Cardinals
5 Cowboys
6 Packers
There's also a simulation for College Football.