PSU for the GX2? (Couldn't help but rhyme it-- 9800GX2)

Though the chances of me getting a 9800GX2 are basically none. I just wanted to use it as a reference point. According to NVIDIA the 9800GX2 requires a 580-Watt minimum power supply.... what?? Thats a fricken ton, and it's only the minimum. My old 7900 GS only requires a 350 watt power supply. I just recently bought a VX550W thinking it would be plenty for my needs over the next 2 or 3 years, and then I look at that card, and think how the prices on it and similar cards will drop in 3 years... makes me think I just wasted $100 on a good unit. Heck I thought this unit would be good enough for a decent SLI in a year or so. If I had maybe 2 Hard drives, 2 DVD drives, 3 case fans, standard mobo, an AMD 6400+ and a 9800GX2, would it run it fine? What about SLI-ed 8800GT's? Thanks