im goin to buy a mac at the end of the month to replace my white macbook. Im torn between the macbook air and macbook pro 13 Does anyone know how the base macbook air 13 and ultimate air 11.6 fair with basic stuff like email, internet, itunes, are HD itunes movies a problem? IS the screen difference really big between the two? also should i spring for the 4gm ram or is the 2gm stock great for all the stuff. Especially HD itunes movies.