I just bought a couple of these for my new sewing room.
http://www.amazon.com/gp/product/B00...00_i00_details So far they are comfortable. They do say they are meant to be used on carpet and if you use them on hard flooring you must get different wheels. I have a different chair by my computer (ReStore for $25) that has slipped out from under two people. Ow! My tailbone hurt for a month. The other person wasn't hurt like I was.