I have been considering for quite a while the idea of a stand up desk, at least at home. My miserable seated posture and the back and neck pain I experience from sitting for hours a day should have been enough to spur me into action. And then I read this:

This is your body on chairs: Electrical activity in the muscles drops — “the muscles go as silent as those of a dead horse,” Hamilton says — leading to a cascade of harmful metabolic effects. Your calorie-burning rate immediately plunges to about one per minute, a third of what it would be if you got up and walked.

Oh dear. Dead horses?
‘Is sitting a lethal activity’, New York Times, 14 April 2011
Edit: There is also an earlier article with moar science in it: ‘Stand up while you read this!’, New York Times, 23 Feb 2010