Could someone please explain the significance of the GPU? I'm going off to college next year and will probably be buying a 15" Pro, but I'm not sure if the high-end model is worth it for me; the slight processor boost certainly isn't. I'm getting a pro because I occasionally do tasks such as hardcore photo/video editing and number crunching (mathematica etc). However, I don't do 3D rendering or anything, so I'm not sure if the 1G AMD would be necessary. I'd like to future-proof my computer (be using it for the next 4 years) and also occasionally play things like NBA 2K11 or COD etc. Would the 256MB version be enough? I really don't know very much about graphics cards.