Oh, and by the way, the chair I bought is a Hag which you can view at this site...
http://www.hag.no/hag_us.nsf/pages/h...sco_ergonomics
I love my chair because it's allowed me to work while in much pain. It allows your pelvis to align properly and the base has built in foot rests, so your pelvis is tilted forward slightly as you work. It also is very comfortable to sit in if you turn it around and sit so the "back" is now supporting your torso from the front with the arms acting as arm rests.
I hope this is helpful,
Ana