hi, for high school next year, i'm required to have a laptop. i already know that i want a mac, but i just don't know which one. i will be using the laptop for most of my classes throughout the school day and for homework after school, so i don't want something that would be really small and hard to look at. (i know that i prefer larger screens over small ones) i dont really care about the portability. i am just wondering if $600 more is worth it for a bigger screen.