The Aeron is made of thin, porous material that supports your weight yet breathes, adjusts in innumerable ways, and looks very Darth Vader. Buying one will cost you about $1000 Canadian. For a chair.
Sierra Wireless Inc., where I'm currently working on contract, just built a new building (another is on the way too -- I can see it out my window), and here, everyone (yes, everyone) has an Aeron chair. I'm sitting in one now. And you know what?
It's just a chair. Comfy, sure, but just a chair. I don't sit here constantly amazed at the privilege. My $99 Hon office chair at home is not quite as comfortable. But it isn't bad, and for 10% of the price, I won't complain about that.