I just bought the OCZ 700watt GameXStream as well, but now that I have read this thread, I am somewhat regretting it. I bought the PSU simply because I had this idea that more watts = better PSU. I know now that I would not even come close to
needing that much wattage for my system. (Just look at my sig.)
However, I was going to go with the Hiper 580watt Modular PSU. It was about 100$, and they had deals and rebates on the OCZ to make it about 119$, and I thought, "what the heck..." Personally, I don't have the time and energy to go through the specs of every component in my system to calculate the minimum requirements for my PSU. I don't think that is really worth it, but perhaps I am wrong.
The question I do have about this subject is this: if I have a 700watt PSU, I am still only drawing the wattage from the combined requirements of my system, correct? ...because if I am drawing a constant 700watts then I had better get a smaller wattage PSU.
Your electricity is measured by the KW/H right? I would hate to know how much it is costing me to play Oblivion per hour with a 1KW PSU.