I'd rate them
None are bad options. I've seen Atlanta listed as a top 4 D at quite a few sites. I'd take them, especially with Vick out. They feel they need to make their mark to get the team to the next level, not Vick - and that was before the injury. I think they'll start off strong with Vick now out. That D wants to take the spotlight, and with Brooking running the show, they should crush people.
GB scares me because they lost Gilbert, and Vonnie in the offseason. Teams are going to run on them all day, or try to. That Barnett (?) guy or whoever they drafted (reach!) is going to be a big key on how the D performs. They're the Packers, so they always manage a solid workman like effort on D. You get KGB for sacks, and Sharper and Co. for picks.
I look at NE's D as being a team that shuts down the pass primarily. They aren't a truly, dominant unit with the big MLB running things like Ray Lewis or Urlacher, or Brooking.
The meek ain't gonna inherit $#!%....'cuz I'll TAKE IT!