Yes, by choice. I moved my work surface up in my cubicle back in November 2012. The first 3 weeks or so, it took some getting used to, with sore knees and such, but now I can stand for the entire day (9.5 hours) and completely forget that I'm standing.

I no longer have any back pain - something that I was dealing with for many years.

Last week, I was attending a Microsoft SharePoint administration class all week, and didn't have my standing desk. I was actually very uncomfortable sitting for long periods of time. I found myself standing up during the lectures, and only sitting when I had to - for the labs.

I share an office space with 2 others, and they both converted their desks to standing as well. One of them stands for only about 1/2 the day. What he did was install his monitor on an extendable arm (ergotron), so that he can drop it slightly below the level of the desk. The keyboard and mouse are a little high for him when he's a in a seated position, but he's OK with that.

There are height-adjustable desks, for those that don't want to stand all the time. I'm sure they're not cheap, but simply by pressing a button, you can change the height. Great for shared working spaces. I'm considering getting one for home, since my wife is 11" shorter than me.

Here's a good example, though far out of my price range: https://www.youtube.com/watch?v=RjiN6Q9wwOE

Sorry to derail the thread...Maybe we should start a new one.