About a year ago, after reading an article in LifeHacker, I switched to a standing desk in my home office. I got sick of tripping over my chair and sitting on my butt all the time. A standing desk seemed like a perfect solution.
V1.0 was just my regular desk with a bookshelf placed on top. I swapped the bookshelf out for a metal shelving unit after a while for added stability.
V2.0 was slightly more artsy. I created it out of snap-together metal cube things... This desk was less stable than it's predecessor, but allowed for more awesome configuration of materials
V3.0 is the current version and it took me most of yesterday to put it together. I've scrapped the sketchy-unstable setup in favor of building the silly thing directly into the wall. I purchased a rather large piece of wood, sanded and stained it in two pieces for installation into the wall with shelving bracket materials from Home Depot. This version is MUCH more stable than the previous setups, and provides me with WAY more desk real estate.
Desk1 : home
Desk2 : Office
Overall, I highly recommend standing desk setups, especially since it gives you an excuse to be on your feet AND use your brain to design/build it.
If you're looking for ideas/inspiration/reasons to give it a try, check out the following links.
The inspiration for my desk: http://lifehacker.com/5874352/build-your-own-standing-desk-for-40
The How/Why of it all: http://smarterware.org/7102/how-and-why-i-switched-to-a-standing-desk
Another one, just cuz we can: http://lifehacker.com/5190734/save-your-back-and-some-cash-with-a-diy-standing-desk
One important thing I've noticed in working at a standing desk both at work and at home: Get some kind of pad for your feet. Gotta have it. It keeps you moving around provides a more flexible support than standing on the ground.
Coming soon: my experience with Sea Level Sucks