I love my standing desk for these reasons. The tailor that did my wedding tux last year also commented on my posture being near perfect. I attribute it wholly (maybe inaccurately) to using a standing desk (and standing most of the day) for the last three years.

Also, maybe it's all in my head, I don't get that "afternoon drowsiness" at all since I started standing up after lunch instead of eating and then sitting in a comfy chair.