I have a few criticisms.
RAMsinks are so overhyped IMO, especially the Dominators. Get some low voltage, low latency G.Skills ECO with no sinks. These run cool at 1600, something the Dominators need sinks for due to their higher voltage requirements and lower tolerances.
The Corsair AX1200 PSU is known to have noise issues, read up more about it and you'll find the Antec HCP-1200 is a far better PSU.
http://hardocp.com/article/2010/10/24/antec_high_current_pro_1200w_power_supply_review/
Google "ax1200 coil whine".
You really should go Sandy Bridge, the motherboards are newer, cheaper, have amazing performance for a fraction of the price of X58 and you can replace it in 6 months and ebay the mobo and CPU if you really want to upgrade to X68. Plus, the Vertex3 and Intel 510 SSD reviews have shown that SSD performance on the Sandy Bridge platform cannot be beat and is miles ahead of the 6Gbps controllers found on X58 boards as per the one you selected.
Great monitor choice!
H50 is noisy and overrated, get Noctua as per other comments.
Definitely WD over Samsung, Samsung HDs tend to run HOT.
SSD, if you will be moving around compressed data, get the Intel 510, if not, the Vertex 3 will be great. Sandforce controllers as found on the Vertex3 are slow when dealing with compressed data such as video.
I have always preferred mATX. With the ASUS SB models you are hardly compromising. The LIAN-LI V354 case below is simply superb, looks pro and doesn't have any of the boy racer look other cases tend to have. But I guess its all about personal taste at the end of the day.
http://www.techspot.com/review/323-lian-li-mini-q-pc-v354/
Are you ever going to fill all those 5 1/4" slots on the 800D?
Count them...
If you don't want to go mATX, get the Asus P8P67 PRO, same great reviews as the once I specced, only bigger. The UEFI BIOS of the current SB Asus boards is excellent and very futureproof.
Here are my recs:
LIAN LI PC-V354B Black Aluminum MicroATX Mini Tower Computer Case
$149.99
ASUS P8P67-M PRO LGA 1155 Intel P67 SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard
$149.99
Palit GeForce GTX 580 (Fermi) 3GB 384-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
$599.99 (may wait for GTX 590 instead, depending on release date)
Antec High Current Pro HCP-1200 1200W ATX12V / EPS12V SLI Ready 80 PLUS GOLD Certified Modular Active PFC Power Supply
$299.99
Intel Core i7-2600K Sandy Bridge 3.4GHz (3.8GHz Turbo Boost) LGA 1155 95W Quad-Core Desktop Processor BX80623I72600K
$329.99
G.SKILL ECO 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL8D-8GBECO
$174.99
x2= $349.98
Intel 510 Series (Elm Crest) SSDSC2MH250A2K5 2.5" 250GB SATA III MLC Internal Solid State Drive (SSD)
$614.99
Pioneer Black Blu-ray Burner SATA BDR-206BKS
$129.99
Noctua NF-P12-1300 120mm CPU Cooler and Case Fan
$24.99
x3=$74.97
Noctua NH-U9B SE2 92mm SSO CPU Cooler
$59.94
Noctua NF-P14 FLX 140mm Case Fan
$29
You will see that the spec above runs cool and above all, silent!
It can hold a LOT of drives and can do GTX580 (590 too?) SLI. I've specced 16GB RAM but the board can hold 32.
Here's a great thread on that Lian-Li case, it has quite the following:
http://hardforum.com/showthread.php?t=1523895