I have 6 of those and I have checked with the kill-a-watt and I can assure you that this is exactly how much power they use.

The rig that sits right next to me at the moment has two quad-core xeons, a bunch of hard drives and 3 of those cards. With all mining it currently uses 460-465W. When I stop the mining it uses 210-220W. One of the other rigs can barely run Solitaire but idles at 45W and goes to 215-220W during mining with two cards.

Oh yeah - and if you trust that page the 5850 should be able to do >400MH/sec. That's a BS - unless you water-cool it and waaaay overclock it. I've undervoltaged them (0.950V), underclocked the memory (500MHz) and overclocked them a bit (775MHz) and they do exactly 305MH/s and are perfectly stable and cool at 65-68C. I guess I could squeeze out another 30-50MH but I have to overvoltage them which makes even more heat and consumes more power - what I gain in megahashes I'll pay in kilowatts.