[marti]

Between the two 'extremes' of standing and sitting, there's also the saddle chair [1]. I've used one at home for over a year now, but only up to a few hours a day, so can't really tell how much it has affected my posture in addition to regular exercise.

[1] http://en.wikipedia.org/wiki/Saddle_chair

[agumonkey]

I wanted to try something like this but didn't have one so I used a stool (4 legged IKEA with thin cushion). Not good, exhaustion feeling comes quickly, bad blood flow I suppose. I never bother searching for a real saddle chair but your post makes me wanna buy one.