These guys are really good at what they do. These sleeves are perfect. They not only provide scratch protection, but also bring you happiness from the moment you unwrap the packaging. Hard Graft have different variations for their covers. There is also have a nifty mouse and charger case which doubles as a mousepad when opened flat.
Our second pick for Macbook covers was the Arkitip Krink Incase sleeve (which is sold out in the 15″ anyway).