[iharris]

I thought that it was obvious that if you stand for 8+ hours, you'll want to be wearing proper footwear and/or have a standing mat. Your entire body weight is borne by your feet - treat them nicely!

Folks with weight problems or diabetes tend to have foot issues as well - exaggerated pronation/supination, plantar fasciitis, and swelling to name a few. There are solutions for nearly all of these problems and are highly recommended for general use, not just for standing desks.

[bct]

Another option is a stool. Having the option to stand can make a big difference, even if you're sitting most of the time.

[jaibot]

In my current setup, I stand between my desk and the wall. I can occasionally lean back against the wall to give myself a break. Between that and a gel mat, I feel pretty good.

[e40]

Not just your feet, your knees, your hips and your back. I can't stand in the same place for more than 10 minutes before my knees and back start hurting. With a good chair, I can sit all day without problem.