I've been using my PB G4 15" for the past seven years. I'm going to be a grad student this fall and have been holding out for a great new machine with better form factor. I was a little disappointed with the WWDC new MacBook pro retina just because it's so darn expensive!! I paid 1499 in 2005 for my Powerbook; I can't see myself spending more than that in 2012. Now the Air is starting to look really good to me. But I'm hesitant because I'm used to my "pro" level laptop; part of the reason I think it's lasted me so long is because it was well-built at the time. How long are these Airs lasting? Do I have a legit concern? BTW I've ruled out the legacy MBP completely. Too heavy, too much of the same old. What's your advice?