I use an office chair I bought at Office Depot (or Max, I don't remember which). The back and seat height are adjustable and it's has rollers so I can roll it around. I've used it for years and really like it.

I second what sahansen44 said! I love my Koala Sew Comfort chair. I too bought a floor model and saved about $50. I used to get a sore back from my old chair and this one is sooo comfortable!

I use an office chair on which the height of the seat can be adjusted. It works great for me because i am short and I need the lower seat setting.