I'm currently building my system and am waiting for bulldozer processors to come out before making a final decision on CPU, although it will probably be either a new bulldozer or a i5-2400 (from early rumors the bulldozer will probably be 95W TPD like the i5, I have no plans to OC the processor so a 2400 is enough for me)
I'm planning on running at most 2 HDD's and a SSD (future upgrades starting with a single 1tb F3)
my current resolution is only 1440x900 so I know a 6850 is enough, however my first future upgrade will probably be a 1080 monitor, and I want to beable to upgrade to crossfire in the future
If the PSU is not enough, I'm debating buying a 6950 right now instead and overclocking later if I feel the need
I probably won't respond for the next two days since I'm traveling but I will look for recommendations as soon as I get back
Oh you're fine. Throwing in five fans, and a couple of external USB devices, with 10% capacitor aging (even though this is a new system), I got only 476W using the PSU calculator at http://www.extreme.outervision.com/PSUEngine. Enjoy your build.
I think the TDP of the 6850 is around 130W. I know its more then 90W. Two in CF would be 260ish, round up to 300W for your board and other stuff. Even if you were using a 95W CPU, your still at just under 400W for the system. Your PSU has a single 40A rail, so you have 480W available. I agree that you should be fine.