About a week ago I put on some Bilstein B8 5100 front/rear for 5-6" lift. Front: 24-185943 (collapsed 17", extended 28.44") Rear: 33-151663 (collapsed 15.9", extended 25.93").
I have a '99 XJ with 5.5" lift and 33x12.50 BFG KO (original) tyres. I immediately noticed that the ride around town felt like I was driving a new car. When going over speed bumps, my head didn't hit the ceiling anymore. My wife even commented that it drives a lot better now, and she hates my Jeep.
Previously, I had on the Rubicon Express monotubes, which were on for about 10 years. They still had their spring back in them, so they must not have been entirely shot. Back in 2003 I put on OME shocks, which ran really nice, but lasted not more than a year or two. I'm hoping to get more life out of these Bilsteins.