49ers - We've had an above-average defense for some time now, but they are truly playing lights out this season. Rookie Aldon Smith is having a Pro Bowl year with 13.5 sacks, giving us that pass rush threat that we've been sorely lacking, Navorro Bowman has been perhaps the biggest surprise, leading the team in tackles. You don't need to say anything about Willis, but his absence these past few weeks has hardly been noticed with the stellar play of backup Larry Grant, and that's certainly saying something. Then you've got Carlos Rogers having his best season ever with six interceptions, and Justin Smith making a case for Defensive MVP on the line. Not to mention the fact that as a unit they lead the league in takeaways, and are just two games away from being the first team in NFL history to not allow a rushing touchdown in a season.