I checked out the skins, and they are great for protecting, but they do leave a noticable orange peel effect--I didn't want my MacBook's shiny beautiful surface to be marred by the orange peel effect, protected or not...
I mean would you buy a gleaming new BMW and then cover it with plastic protection that would leave it with a rippled surface...?!
I use iDrops and cotton balls--very mild--every few weeks and remove the scratches, which are mainly on the bottom. I'm good about protecting my computer, so this is not a big chore, but some might not want to polish every few weeks, or have active computer styles that produce too many scratches or too deep of scrtaches to be removed with regular polishing. These people are ideal candidates for skins (plus they are so busy and active they won't notice that the surface of their computers looks like Florida's finest).
I really do reccomend the iDrops (best price on Amazon.com)--you need elbow grease but it works great to remove scratches. Use it with pure 100% cotton balls to leave no swirls or marks. It's also a superlative basic cleanser/polish for the white MacBooks and iPods.
I like to get my aggressions out while polising, and the MacBook looks ultra shiny and like new afterwards, and I NEVER have to live with the orange peel effect that the skins add to your MacBook....