Since you will be using a 6950 crossfire, make it 1050w or 1200 would be better, my other advice would be if you can afford those parts you should squeeze an ssd or a velociraptor, that kind of drive seems out of place, you got a 300$ procie, 500$ graphic cards, more than 100$ memory and a 400$ mobo? and the drive you'll be using is what, 60$? Also you sound rich, how bout adding a water cooling setup, koolance maybe or EK.

SSDs are definitely worth the money. With two of corsairs newest 6gb/s ssds in raid 0 im getting up to 800MB/s reads speeds using my onboard raid controller. And also, don't put that size of hard drive in raid 0, I assume you will be using that same raid array for documents and other important data so with raid0 your are doubling the chances of losing your data. I recommend using the SSD for just apps and games and your os and use a hard drive (maybe 2 of them in raid 1) for all your data. You could get away with using an 850W psu but its good to overdo it a little so get one around 1000W.Sounds like a beast system your building there:)