Ok. I decided to drop Fusion Drive and go for 512GB SSD Drive. I never managed to fill my old 320GB iMac, so I bet it's good size. I plan on using the iMac for the next 3-4 years. Will 512GB holds fine? I'm going for the i7 3.5GHz, 16GB RAM and GeForce GTX 780M. What if I go with standard i5, 775M and the 1TB SSD instead? Would I lose much gaming performance? I don't live in the US and have to wait a month to get my iMac after ordering, so there can't be any mistakes, it has to be bullet proof after shipping.