I go in and out of liking laptop skins; sometimes they can look cheap and dumb, and sometimes they're done right and end up looking so adorable that I want to buy a whole series. Making a good case for the latter scenario is this Tree Laptop Skin ($19).
It would make your laptop so cute and distinctive that no one would mistake your MacBook for theirs while you were up getting your third coffee at Starbucks. That makes it valuable and beautiful. Like you.