You're lucky it's just cosmetic. One of mine was in its second skin sleeve, and in a padded laptop bag, fell off a luggage cart at a hotel from about 4 feet onto the carpetted floor and sustained a very slight dent on the rear right corner.
I was able to straighten it out, but the display lid clutch appears to have taken the brunt of the damage - there's now a bit of play in the display lid, probably about 1-1.5 inches worth. Annoying as hell while im on the train, as it wobbles like a dashboard hula girl doll.
I figure I'll pop in at an apple store and see if they'll offer to fix it under applecare - if not, I'm sure its gonna cost me a pretty penny, in addition to blowing the applecare away.
Oh well, live and learn. Plastic might've fared better in this spill.