I need a to get a new computer and I was planing on getting the new low-end 13" macbook pro, but the new upgrade isn't what I expected as far as the GPU goes. So I thought that I would get the macbook pro that would retain it's value the most and sell it when the next and hopefully redesigned one comes out next year. I would prefer to spend as little as possible so from the smallest screen size and up which one would be the be the easiest to sell when the next one comes out?