Some sound advice, some shocking.
SSD is unnecessary, especially since there's a limited number of times it can be written and rewritten.
850W might be a bit much, it's just going to hurt your electricity bill
I don't know which comment is more shameful. The former suggests you are so far out of the hardware loop that you shouldn't even be contemplating giving advice on ssds, and the second demonstrates that you know sweet fa about electricity. Not a good post.
This man is repeatedly recommending fan clips made for a specific, nominally passive air cooler to use with a completely unrelated product which doesn't need any.
SSD isn't really 'unnecessary' as it is much faster...
850W may be a slight overkill... The Corsiars are fairly efficient. If anything it will help his electricity bills.
Xonar and X-Fi, they are just better at different things...
The fans he has chosen are superb...
This man's on the ball though, I agree with everything he's said.
Single card over dual is normally preferable, it avoids general driver problems and cuts the noise of the system considerably. The 285gtx is a beast, even faster than the monstrous 280gtx but not as inclined to burn a hole through the side of your case.
Processor and board I like so much I own them. The ram is what I would have bought if I wasn't fixated on watercooling everything. I'd want the 850W corsair personally, since it'll be cooler and stressed a lot less. I massively overspec power supplies though, a 400W would drive my system fine and it has an 860W in it.
Not the ssd I'd have chosen. Personally I'd want an ocz drive, either the 60gb vertex or the 120gb agility. Probably the latter, I'm using the amazing vertex at present but would have bought the saner agility had it existed so long ago.
One thing to consider, though it would be a complete rework of a lot of your spec. You've not mentioned a case. Or water. So I'm going to assume you're air cooling and would like a new case. I strongly recommend the exceptionally good antec mini p180. It will do an excellent job of cooling your graphics card and hold the corsair cooler with no problems at all. It requries a move to matx, which means evga/asus/msi who all make lovely matx x58 boards. Who on earth uses 7 peripheral cards these days though. Of course you could use the P193 or similar, and it'll cool a bit better, you can use the amazing gigabyte board and fit mad numbers of hard drives into it. It'll be bigger though, and small is beautiful. Computers that manage to be small, beautiful, quiet and obscenely quick are perfection in my eyes.
Cheers