If you spend a lot of time at your computer, and I know you do, a wrist-rest is a must.
Especially during these winter months, when desks, tabletops, and other work surfaces tend to get chilly. Of course, a properly elevated wrist is also less likely to develop repetitive-stress problems.
You can buy a wrist-rest, sure, but why spend money when you can make your own using any number of household objects?
For example, I often work standing up at the bar-height section of our kitchen counter. It's made of granite, so it can get really cold.