Power Supply for advice for this config?

Well the wattage I have on my computer is about 750 watts, and it works well. With the 1 terabyte hard disk however you might want to go to 800, no more than that though because its not necessary to go any higher. You could probably even go with about 500 or 600 watts and still have good performance. It all depends on what you do with computers. If your concerned on saving electricity than 600 would be a good choice.