I have a Mac Book from the aluminum uni-body series, it runs great and I have no problem with it. However I am a grad student now, and I walk to school a lot, and last semester I was really bummed lugging it around in my bag everyday. I am thinking about selling it and getting a Mac Book Air. The questions I have for the form are this. Am I going to notice/miss a change in performance, and will I be able to get by and do the same things I enjoy now, with the Air as my sole computer? Such as watching netflix youtube etc. And how much could I expect to get for the Mac Book on Craigslist? I have a large external hard drive that I already keep my music files on. Also I plan on upgrading to a wireless version soon. Thanks for your opinions!