Case wise, there's pretty much just Speck and Incase that are interesting and have the advantage to let you use your MacBook with peace of mind while you're away of your clean desk.
Incase seems to be better, easier to put it on.
Speck is better looking, but seems to have the negative point to scratch by accumulating dust it and rubbing on the surface. It's also harder to remove, depending on the technique you use.
Personally, I own a Speck because there's nothing else available for me. I remove it every 2-3 days to avoid any scratch from dust. I also use the credit card method they show on their website. The removal seems pretty brutal, but the unibody construction seems strong enough to resist it without any scratches or abuses to the finish. So far that's what I can tell. Quite happy of this purchase.
There's also the Zagg invisible plastic film that you apply on the notebook. They claim that it can make the finish completely scratches proof. I don't like it, and give absolutely no protection against dent while hard case can help to avoid until a certain extend.
