If you’re a coffee drinker, or just want to be extra careful, I highly recommend the following keyboard cover:
It’s a silicone-based keyboard cover, which you do not have to remove to type. It will protect your keyboard from dust, liquid, hair, etc. I use it myself and I’m going over a year strong, and I have no regrets. Did I mention that it’s washable?
They also have a variety of other protectors for your iPod as well. You should check it out, before the coffee spills on your Mac!
FYI, you can also try to look for their products on ebay, and you might find some of them to be slightly cheaper – but not by much.