In addition to this question it would be good to know where to go to try out all of these chairs that are mentioned. Most places I've been only have the cheap ones out for trial.
There's a chain called "The Healthy Back Store" and that's where I went to try out chairs. I ended up buying the Nightingale CXO chair, which I hadn't heard of until I went there. They also have a good online store -- http://www.healthyback.com -- but obviously that's not a great place to try out chairs.
