15 inch pro. And if you are not into gaming or 3D graphics, I would not get a dedicated GPU. Might increase the lifetime of the machine a bit (less heat inside)

15 inch pro. And if you are not into gaming or 3D graphics, I would not get a dedicated GPU. Might increase the lifetime of the machine a bit (less heat inside). By the way, the iGPU is good enough for games like Hearthstone, League of Legends, etc...