In my experience the AD on 2008 was "firmer" than on the current 2011, the later having a bit more body roll, but still can't imaging getting one without AD!

__________________
---------
Hers : 2013 335xi Imperial Blue/Black with lots of stuff...
His : 2013 X5 35d Deep Sea Blue/Black with all packages
Previous : 2010 335xi Monaco Blue/Black with just about every option...
Previous : 2008 X5 4.8i Space Gray/Black with just about every option...