Since the season of colds and the flu is upon us, the Seal Shield Keyboard and Mouse might be worth the investment, especially if you share your computer with a couple of people--or kids, who seem to be especially good germ carriers. The Seal Shield keyboard and mouse are fully washable, including in the dishwasher, and the mouse pad has silver in its construction, so it's anti-microbial properties won't wash away.
What sets this apart from using wipes to just wipe down the keyboard is that you don't have to use harsh/unnatural chemicals to clean it and then get them on your fingers, or on the fingers of your little kids, who are all the more likely to put them near their mouth, eyes or nose. You can use a natural soap, give it a good rinse under the sink, and be ready to go.
The keyboard and mouse set retail for $100, although the keyboard is available by itself for $50.