Oh don't get me wrong -- I'm really glad I've got mine. I took a look at my Dell Laptop (my work issued one, the one I never use 'cause it's, well, a Windows box), and I was amazed at how gross my keyboard looked. Likewise, the keyboard I've got attached to my Mini was so gross that last month I pulled all the keys off and washed them in the sink.
As long as you mind the screen, I think the iSkin is a great investment. It does take a few days to get used to the increased resistance when typing however. Even though I'm quite used to it now, I do still prefer the feel of the keys without the cover, but not enough to warrant dingy food-encrusted keys! :biohazard
I agree that the wrist-rest protectors are a great idea. I don't have them, but I really should get a pair. The MBP gets really warm there and I frequently sweat a little, and I'm afraid I'll discolour the surface if I don't put something there to protect the surface.