I won't go as far as listing my top five, but I'll give a couple of comments.

As mentioned above, the Giants have the best d-line in the league, made numerous off season acquisitions, and get Osi back... get off it, they're going to be nasty.

As far as sleepers go, I would look at an unlikely option in the Cincinnati Bengals. The addition of Tank Johnson and Rey Maualuga will help stop the run, plus they will be getting back their 2008 1st round LB Keith Rivers (as long as he can keep his teeth in his mouth if he takes a hard block). Throw in Roy Williams to an already strong secondary, and I think you have a marked improvement over last year's #12 overall defense. Whether or not it will translate into fantasy success is yet to be seen, but the talent is there.

Of the obvious choices (Pittsburgh, Baltimore, NY Giants, Minnesota), I think the Vikings have the best potential to continue to ascend and do something special. If their offensive additions are successful and they're playing with larger leads, the defensive front should simply shred opponents for a huge number of sacks and turnovers. The Vikings play a pretty easy slate of opposing offenses as well. The one concern is the possible suspension of the Williams Wall, which I believe still hangs in the air (true?).

Fallers: Baltimore, Tennessee, Tampa Bay. All three teams lose elite defensive coaches and the first two lose key players. Moreover, all three teams are way below average at QB and WR. These teams will be scratching and clawing to stay in games, not exactly the formula for pinning your ears back and getting sacks and turnovers.

Sleepers: Arizona, Indianapolis, Cincinnati. The Cards are a great boom-or-bust defense. As a reality defense, they were way below average at times last year, but they have a lot of playmakers and the playoffs showed what they can do when everyone's on the same page. They should be improved this season and their schedule is so easy, they'll be up two TDs by mid-second quarter most games. Expect lots of sacks and INTs.

My dream for the Colts is the new coaching staff eliminates the philosophy of playing prevent defense the entire game. If they can get more early possessions for Peyton, they can jump on teams earlier and get more opportunities late for Freeney and Mathis. This team could be like the 2003 Chiefs D, a crummy reality D that leads the fantasy world for most of the season.

Everyone's sleeping on the Bengals because their record was so bad, but they're finally starting to build in some depth. They finished 15th in defensive DVOA last season with a weighted performance of 9th (that means that down the stretch they were better defensively than teams like Miami, NYJ, Tampa, Car, Wash). With Palmer to give them some protection, the young defenders should continue to improve. Like all the AFC South teams, they face an easier schedule in 2009. It will be interesting to see whether their overall defensive success translates into stat accumulation. The Bengals did not get many sacks or TOs last year. Their whole division may feature extreme offensive conservatism in '09 which makes stat accumulation more difficult. They may be a better fantasy defense in leagues that heavily emphasize points allowed.

I think you have to put Washington as a sleeper D. There is a reason Haynesworth is a 100 million dollar man. I dont think they will be top 5 due to their division, but top 10-12 is well within reach.

Defensive ranking are irrelavent for the most part though. San Diego was the consensus #1 last year and look what happened.

Put the usual suspects in there, Steelers, Pats, Giants, Jets and Chargers and call it a day.

Matchups are much more important with D than any predetermined rank.

Sleeper D: Packers

They had a very good 07, but a terrible 08 due to injuries and line ineffectiveness. Obviously the corners (Harris, Woodson) are still old, but an improved line and a new scheme (3-4) should help curtail those long runs.

They also appear to have a weak schedule and perhaps a 40-year old QB in the division.

I have more work to do, but see Eagles and Jets approaching the top 5. Rex Ryan has lots to work with, and an improved offense can only help Philly.

As far as sleepers, I like Dallas, Miami, and San Diego (if it truly is) – in that order. I especially like DAL/MIA value. All three had strong finishes (weeks 14-16) to the season (and Merriman wasn’t playing then either), and did well enough overall to be within range this year.

One team poised for a big fall is Tampa. They had a huge drop off late in the season, and I haven’t seen how the off season will help them.

I hate new schemes as a reason for success. Schemes often take a few years to implement, both in learning for the players and personnel to fit it. The Broncos and Chiefs will be better (simply because they shouldn't be worse), but I the Packers will be worse. They survived on D/ST TDs (like 8 or 9).

Teams that could surprise:
Bills: T.O. means the offense stays on the field and keeps the defense off.

49ers: A return on offense to grind it out football keeps a defense off the field that has 10 returning starters.

Patriots: Addition of Leigh Bodden, Shawn Springs, and Darious Butler made Ellis Hobbs expendable.

The Baltimore Ravens finished as the top DEF in my leauge, I dont see why they wont do it again...... oh wait, scratch that.

What I meant to say is the New York Ravens should finish as a Top 5 team. Rex Ryan has already shown that he will do whatever it takes to make sure that happens.

The Jets D should help keep them in games and take some weight off the shoulders of their impending rookie QB.