[thisisdallas]

I've always bought cheap generic office chairs but recently picked up an Herman Miller Aeron. I am honestly surprised at how much of a difference it makes. I use the Aeron at home and have a generic $150 office chair at work and I am really hating it after getting the Aeron.

They are pretty expensive so you might check on Craigslist for a used version, that's what I did.

Also, you might try a standing desk. I've heard/read great things and will be getting one pretty soon.