I'm very very protective over mine since my late 2011 15" was a generous gift from my family, so I figured spending less than 10% of the price of the computer in order to protect it is no big deal. I have a Speck See Thru Satin in black, Moshi Clearguard to stop oily keys and dog hair and debris, and a Caselogic PAS 215 sleeve. When I travel, I put all of this is my dads old briefcase which means my computer is more than protected. I just don't want to risk any damage when it was such a wonderful gift. It's my baby.
. Cheers everybody!