I wouldn't carry it around in your hand. You'll probably drop that before you break it in a backpack. Just get a cool backpack that has a laptop sleeve. I actually just launched a backpack brand that is perfect for Ipads, Macs and up to 15" laptops. www.facebook.com/revivebackpacks
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Herschel has some dope, Mac oriented backpacks. I travel a lot with a laptop on, and with a sleeve it should be fine thanks to the padding most backpacks have. Honestly though, as long as you don't throw your backpack everywhere, you should be fine. http://shop.herschelsupply.com/shop/heritage-4094.html
No, use a herschel backpack. I love mine, perfect for traveling. I've been using it for a good 9 months now for everything...school every day, trips, etc... still holds up. I always keep my laptop in there while traveling. They're only like 45 bucks too, I highly suggest checking them out.