Here are some outside links that tie into the Chairs episode.

Ergonomic Workspace Planner

Just punch in your height and this diagram gives you the proper distances to adjust your chair. [Lifehacker]

The Four Best Ways to Sit at Your Computer

This list ranges from the simple (exercise ball) to more complex (treadmill set-up). I’ve heard good things about the exercise ball but I just don’t see it being fun after long term use. [Lifehacker]

How to Sit at a Computer

Very nice step by step list to properly setup your chair and workspace. [Lifehacker]

Russell Executive Mesh Chair

This $230-$300 is an Aeron knock-off that gets a good review from Kevin Kelly.

Flexible Love

Quite a cool accordion chair design that can be setup in many shapes and seat up to sixteen people.

Office Ergonomics

If you have the time, this is a thorough slide show presentation that covers all the correct workspace distances and explains why. [Lifehacker]