Mac Skin - Gelaskins*
Gelaskins is a website that allows you to decorate your phone, iPad, kindle, Mac or laptop with one of the many pieces of artwork displayed on there from hundreds of artists, needless to say I spent a couple of hours pouring over the awesome artwork before I decided on the above one! Mine is by the artist Lora Zombie with Nanami Cowdroy being another favourite artist of mine on there!
Rather than encase my Mac, a Gelaskin is an adhesive sticker that is easy to apply and re-apply if you are not happy with its positioning, without leaving any sticky residue which is great! It protects the back of my Mac from scratches whilst looking insane - I'm already considering buying one for my iPhone!