I’ve been living with my standing desk for several days now, and am a convert. This layout has enough room for my two screens, my Bamboo pen-pad (instead of a mouse), and of course tissues and water. One key part of the setup: the gel footpad (recommended by my SIL—thanks!).
Curiously, my Fitbit gives me very little activity credit for this. I do accumulate a few steps from being upright (but only a few), but it still records me as sedentary.