I thought others might find this Arstechnica article informative...

Taking a stand: my experience working at an elevating desk

"As a professional journalist and software development hobbyist, I generally spend between eight and eighteen hours a day using a computer. This effectively keeps me chained to my desk most of the day, and sometimes late into the night. To combat the physical discomfort of prolonged computer use, I reinvented my home office environment with a focus on ergonomics.

The first thing I did was purchase a better chair—that's easily the most significant thing that you can do to make your office life better. After that, I started to look at desks. Last year, I became intrigued by the idea of a standing desk—a surface that is high enough to accommodate working from a standing position. Further research into the subject convinced me to buy a height-adjustable desk that can elevate to a standing position. After using it for most of the year, I doubt I'll ever want to go back to sitting all day."

Standing desks are great. I use one that has a treadmill placed under it so I can occasionally walk while I work. I also have a tall chair that sits on top of the treadmill for when I get tired of standing.

Alternating between walking, standing, and sitting rather than just sitting all day definitely feels better for my back at the end of the day, although my feet get tired if I stand on them for too long.