Hello.I just bought a 2011 11" refurb and really want to keep it protected.My problem is that I must chose 2 Accesories to get out of a keyboard cover,hard shell case,palm guard and Screen protector.Which two accesories would you get to maximize ptrotection on your macbook air?I am looking to re-sell this macbook in about 3 years so I would like to sell it in close to mint condition.