Hi - I just bought a 15'' MacBook Pro (the new unibody, black keyboard style, obviously) and I'm loving it. Of course, I want to keep it protected. So here's what I'm wondering - if I buy this, would it be a good idea for me to also get a sleeve to put around the computer, in the See-Thru Satin case, for extra protection when carrying it in my backpack? If so, what's a good sleeve that would be able to fit around the computer AND the case? Thanks.