Okay I just bought a 13" MB pro and i'm going to be using it primarily for photography. Editing photos in photoshop CS5 and Lightroom 4. At any given time i'll probably have the browser open, itunes, and photoshop or lightroom. I just bought the model with 4gb. How much should I buy now though. Should I really get 16gb? Or just buy one 8gb and have 8x2 so 10gb of ram? Or an 8gb and a 4gb? I appreciate everyone's help here! Thank you.