[pooMonger]

Interestingly enough, from what I've read [1], a slight lean to your posture is actually recommended, and considered the healthiest position when sitting in a chair for long periods of time.

I've purchased <$120 chairs for a long time from the usual suspects, Office Depot, Staples, etc. and the padding in the seat just goes to shit after a year. As if I'm sitting on wood, resulting in lower-back-pains galore.

Today, I'm using a Humanscale Freedom with headrest that I got off craigslist used, but reupholstered, for $400. It's one of the best investments I've ever made. I sit in this chair up to 10 hours a day, and not the slightest bit of back pain.

Can't recommend it enough, so my advice would be to seriously consider stretching your budget ever so slightly. Your future 70-year-old self will thank you (and me if you remember this recommendation!).

[1]: http://news.bbc.co.uk/2/hi/health/6187080.stm