A few things I glossed over in the game preview:
Turnovers and penalties. Obviously the team that commits fewer and forces more has the advantage. A turnover differential of one will probably not sink either team. More than that, and chances increase dramatically. This is the playoffs, and errors become even more pronounced.
Field position. Give San Diego a short field, and they'll kill you. There's going to be a lot of pressure on the Patriots coverage teams to limit the Chargers returners. And the offense can't afford more than a couple three-and-outs, especially if deep in their own territory, and not with punter Todd Sauerbrun, who is still a bit of an unknown quantity.
Time of possession. This is more important in the beginning of this game. The Patriots could use a couple nice sustained drives to wear down the Chargers defense. Likewise, the defense needs to play well and get off the field quickly. The key is to keep Tomlinson on the bench as much as possible.
The Chargers do what the Chargers do. Unlike last week's game against Eric Mangini's New York Jets, San Diego doesn't have a lot of complicated defensive schemes and change a lot of personnel. They keep certainly players on the field and rely on defensive endurance and long offensive drives. A no-huddle won't be as effective as it is against other teams. But it can't hurt. Enjoy the game, and Go PATRIOTS!!