^ Your config is very nice- i wish i could have a pc like that.
May i suggest a few things?
CPU Cooler: Corsair H50 or Cooler Master hyper N620?( Decent amount of OCing not very high)
dump both. Get a Noctua U12P SE2 for build quality and good performance with silence, Prolimatech Megahalem/Megashadow for good performance (Noctua D14 is very big )
RAM: Corsair Dominator 6 gb(3X2gb) 1600 Mhz
Please do check for RAM compatibility with the motherboard you buy. Dominators are good usually but have their own quirks at times.
Graphics Card: GTX 460 SLi
If you can afford GTX460 SLi and can manage to tweak the computer on your own for any issues, you may try GTX460 SLi.
Hard Disk: 2X1TB Seagate
2x 1TB Seagate = 2x 3.2K (?) odd > 6K.
Get a 500GB single platter for OS and a 2TB for dump
Power Supply: Corsair HX 850( Is it enough?)
Good Choice no doubt.
HX750 will suit your present requirements equally well i feel and save you some money without compromising over any advantages the HX850 provides.
But if you want HX850 and afford it, i cannot say no obviously.
Cabinet: Cooler Master HAF-X
UPS: APC 1kVA
Monitor: Samsung PX 2370
Keyboard: Microsoft SideWinder X4(+ some mouse)
OS: Windows 7 Home Premium