Hello, I have quit a dilemma on my hands here. After searching, researching, asking questions, etc., I have finally decided on buying a Macbook Pro for college after looking at some very impressive laptops such as the Samsung Series 9 13", Lenovo T420s, and Lenovo X1. Right now, I am debating whether I should get the 13" or 15". The ONLY reason I would buy the 15" is for the higher resolution(1680x1050) matte screen. Also, the 7200rpm HD worth the upgrade? The 13" would much better suit me as a college student due to its portability and weight. However, I am trying to convince myself that the 13" 1280x800 screen will be perfectly fine for me. Also, if I do end up purchasing the 13", is the upgrade to a i7 worth it? I am going to be studying computer engineering and will be using several different engineering applications, and other applications such as Photoshop, xCode, and Eclipse. I know you may be thinking "Why is a computer engineering student asking these questions," but I'd much rather get other opinions than assure myself that I know everything 100%. Thanks for the help! So... 13" or 15"??