Here's some power supply (PWS) info to consider as you buy a 6800 LE/GT/Ultra:
For those of you who have a PWS less than 480 watts, since this card uses what appears to be an Ultra fan setup, you should know:
1. eVGA recommends a 480 watt PWS for an Ultra
2. other mfgs recommend down to a 420 watt for an Ultra
3. Some say they have run the Ultra on 350 watt cards with no problems.
4. A PWS probably needs at least 30+ watts ON the 12 VOLT RAIL to be adequate for overclockers with lots of power hungry components.
5. A stable power supply is a VERY good idea for this card, especially if you want to OC it. ... ie, a cheap PWS (say $50 for 500 watts) MAY not power the card so you can open it up fully. (Depends on the quantity, quality & stability of the 12 volt rail power.... 30 watts min).
6. Several manufacturers offer PWS that have shielded or power stabilizing cables that will help supply clean poweron both card connections and that's very important.
7. Skimping on a PWS in a hot setup is short sighted.
8. There are several good quality PWS mfgs, Antec, Enermax, OCZ among them.
I ordered an OCZ 520 watt unit for about $130.00 including shipping from Monarch. They have adjustable pots that are adjustable from the back with LEDs that indicate over or under voltage so that's easy to do, they got good reviews from several thorough reviewers, they have a great set of cables including two individually shielded ones I can plug into the card leaving several hydra headed ones for the rest of the stuff and it has a couple of SATA cables. Finally, they are HEAVY, always a good indicator of quality in a PWS.
While other PWS may run the cards, they'll run better, more stable and faster with a good one, especially if you want to OC.