I currently have a 2008 aluminum macbook 2.0 ghz core 2 duo with 4gb ram. I am starting grad school in January and will be riding public transportation every day so I think a macbook air is the best choice for me due to portability. Now, I am pretty set on staying at a 13 inch screen size but I'm really torn with ram and hard drive size. I'm looking basically just at the refurb machines from apple and really leaning towards 2012 models due to the usb 3.0 and slightly better graphics. Anyone have any input? I haven't upgraded in awhile and am a bit lost.