So this house has one 1st Gen 17" MBP (5 year old I think) and that is still going fine although the drive can be reluctant to return disks. It has been submerged once fully in water then dried, dropped twice on the corner but still refuses to die.
12" MBP, better cared for one careful lady owner, but now missing a couple of keys and the battery wont stay in, otherwise fine. Wife claims never dropped.
15" MBP 3 years old, screen died costs way to much too replace, out of warranty so now sits attached to screen. Case lost all silver where hands rest as typing (so definately don't brasso the MBA as it will go black if the finish is anything like MBP). Case is badly bent following a monstrous drop down a flight of stairs on London Underground (screen survived that by a year). Reckon this as the worst build quality of them all.
17" MBP latest Generation, wearing one of those plastic cases (in blue) which works well but really does nothing for the looks. One drop 4 ft to floor case around express slot warped a bit but other than that seems good
13" Macbook, in pink plastic case and definately best build quality
This all bodes well for MBA IMHO so looking for one soon;-)
Almost all of them are thrown in bags without cases, I cycle 25 miles to work and back with them in messenger bag so fair to say I am not what one would call a precautious owner. Ah yes the latest 17" also survived being in bag when White Van wiped me out on bike in December...
Unashamed plug although I am in UK I get all my bags custom made by Ro and Ellie at Reload -
http://reloadbags.com/bags/smcivie.php
They can make pretty much any logo for a price, and for the overly protective among you even do a padded bag... !