i have the BestSkinsEver full body skin on my 11" air. I've been using BSE on all my electronics and it has never failed me. I personally like how it makes the laptop glossy, but moreover, how it gives some grip to the hardware.
Anyway, I like BSE in general because their products are relatively cheap (cost-wise). Specifically, though, for the MB air, I like how it provides skins not only for the usual top/bottom/palmrest/trackpad but also both sides (by the ports) and the back side (where it's black). I was hoping they'd at least give the option of having skins for the empty areas around the keyboard and around the screen (bezel) for ultimate protection but it's fine as is.