What should be here ?
You would not need that much of a power supply even if you add 2 cards and run them at stock. A good 600-650W unit would be enough if going AMD or a 550W be more than enough for Nvidia. As for the cards, I'd get the 950 if going below 200$, but go with the 380/X with 4GB of memory if going more than 200. What resolution are you planning to run ?