Let me preface this--I always feel the same way about fantasy defenses as I do about kickers. That is, it's often hard to predict and scores can swing wildly from week to week. But if you have a good one, the best part is usually that you have some semblance of consistency at the position. This is also a position in which match ups can be important. For instance, if you have a floundering D/ST mid-season and they have a bye coming up, you can often find a mediocre D that might be going up against a young QB who is prone to interceptions (and maybe pick-6's).
Here are a few other thoughts on defenses in 2012:
New York Giants--well duh. But still, many pundits have the Giants' defense somewhere between fourth and tenth. And let's face it, the Giants' D struggled mightily last season, ranking 25th in points allowed and 27th in yards allowed. But the G-men had 48 sacks, tying them for second in the NFL. Their 20 picks also had them tied for sixth in the NFL, but the Giants only had one defensive touchdown. This year, I think JPP will have a couple of defensive scores.
San Francisco 49ers--well, duh, again. We know how hard-hitting this team is and how stout they are in giving up points and yards. The Niners also had 42 sacks and had 23 interceptions, with 18 forced fumbles. I would have no problem drafting this squad.
Baltimore Ravens--well, d--okay, you get the point. These first three are all solid defenses. The Ravens ranked third in both points allowed and yards allowed and tied with the Giants with 48 sacks.
New York Jets--Wow, Rex has a way of disappointing fantasy owners, doesn't he? I had the Jets the last two years and they failed miserably--they give up a lot of points, they are mediocre in sacks and picks, and just had too many games in which they laid an egg.Detroit Lions--This is a streaky defense, but there was one week last year that the Lions had 7 sacks, two touchdowns (a fumble and an INT) and allowed 10 points. They also laid some eggs down the stretch--but while Jim Schwartz has a high-flying offense, don't forget he's a defensive coach and has a crazy monster named Suh clogging up the middle.
Green Bay Packers--31 interceptions last year to lead the league by far, but they gave up more yards than any other team. Think about that--last in the league in yards allowed and they won 15 games.
Houston Texans--JJ Watt is only entering his second year, but he's a JPP-like freak and I know you guys will be hearing his name a lot this season.
Pittsburgh Steelers--always consistent, almost always a decent fantasy D.
Philadelphia Eagles--they will get their sacks and not give up a ton of points. But I'm not touching them and I know most of you won't either.
Chicago Bears--they almost always let me down when I draft them, so I just avoid them.
Indianapolis Colts--yeah, if you like to lose!