Those cheap, "high wattage" power supplies are pure crap. They will never put out that wattage at normal operating temperature. They watt-rate their stuff at room temperature (or less), "just turned on" degrees.
So the most powerful card currently is an Nvidia 6800gt? That is only 256mb correct? Should I wait until someone releases a 512mb card? How long might it be before we see one? I just want to have the most up-to-date card when I purchase in one month.