I'm another data point. Built my own standing desk and bought a drafting chair; I frequently stand most of the day, and it's improved my posture markedly.

I'd gone through a series of various expensive "ergo" chairs, and yet I would get a feeling of suffocation when sitting for too long. Now I can work for extended periods without the need to "get up and walk around."

And when particularly good music comes on the radio, I can dance to it during compiles. Yes, I work in an office where no one can see me. ;)