I find refresh rate extremely important. I stuck with CRTs at 100Hz+ for a very long time after LCDs became popular because only 60Hz LCDs were available. I now use a 120Hz LCD and it's much more enjoyable than 60Hz. Everything feels smoother and more responsive. The improved mouse control is very obvious (this might require increasing the mouse sample rate, I use usbhid mousepoll=2 on Linux). Motion appears much sharper, because the higher refresh rate allows for higher frame rate which reduces sample-and-hold blur (see http://www.blurbusters.com for detailed information on motion quality). The fastest LCDs on the market support 144Hz. I'd like one but I can't really justify the expense right now.
However, note that I am unusually sensitive to motion artifacts, eg. I am bothered by PWM dimming of LED lights well into the kHz, and I greatly dislike 3:2 pulldown judder. It's possible that some people genuinely don't mind 60Hz LCDs, although I wonder if that's only because they've never used anything faster.
Continuation of: Spend Money on Ergonomics, by Kevin
Three years have elapsed since Kevin wisely told us to spend money on treating our bodies well. It may be time to check for new gadgets, to verify what has worked and what has not etc...
If you have purchased an item for this purpose, or intend to buy one and don't know which, tell here, ask here.
Nick Bostrom uses a mouse that looks like a plane controller joystick.
I've seen keyboards that bend sideways, that are concave, that are convex, and that look like a sphere.
At FHI, dozens of books are used so that computer screens stay at eye level or above.
But I am no expert and I have not looked myself, nor would know how to. So please share in the comments the best knowledge about:
Keyboards
Mice
Chairs
Balls to sit on
Pillows
Beds/Matresses etc..
Screens - Size, position, brightness etc...
Other household office items - Stairs, Handles, Shower etc...