Dean, you're gonna laugh, but I'm actually using a DRUM THRONE for my studio chair. I have a (short) history of back trouble thanks to injuries while I was a concrete test technician (summer job). I'm also a professional violinist, which can be pretty tough on the back, particularly an injured back. Add to that the fact that I've got a long torso, and I'm a great candidate for physical therapy.
That said, the drum throne, more so that any other chair I've used anywhere, requires that I sit upright with good posture. It also is incredibly easy to access and leave. So I find that:
1) While I'm on it, I sit correctly and strain my back less
2) Since I don't have to pivot or move it to get up, I get up and move subconsciously all the time. I'll find myself standing up to listen to a take or jumping up to grab something just a few feet away.
3) The posture that I have while sitting on the throne involves my leg muscles for balance and support. So it spreads the work of balancing my body to my largest muscles and keeps those muscles warm and active.
There was actually
some recent research that points to long periods of sitting as a culprit for many Americans' weight problems. [My mom is an RD/LDN, so I talked to her about it.] Apparently there is some part of the metabolic functions that totally shuts down when one sits for a long time, resulting in a huge drop in burned fat (if I remember correctly - this is a bit out of my league). So the the drum throne is good for more than anatomical reasons.
If nothing else, it's cheap. You can get a simple but well-built throne from GuitarCenter for about $30. You might try it, because at that price you have nothing to lose. It's the best studio/computer chair I've ever found, in the 16 years or so that I've been tied to a computer.
I've got mine set up at a height so that my knees are a few inches below the seat when my feet are flat on the floor.
NOTE: The throne was a bit uncomfortable for the first few days, until the seat pad broke in. I know that sounds kinda weird...but now you know.