I have a mechanically adjustable desk from http://multitable.com/ - the hand crank is kind of pleasing. It's not as fancy as the electric motor desks, but then again it doesn't have an electric motor...

I'm actually using a tabletop that I bought from Ikea for the desk surface. I just bought the bare frame for the desk from multitable to keep costs down.

I think all in all I paid around $600. It's pretty nice.