I would suggest...
getting a new monitor...ASUS LED monitors are great, got 2 myself and love them.
850 watt PSU is overkill, save some money and get the Corsair TX750.
if you are going to overclock your CPU, get an aftermarket heatsink, Cooler Master Hyper 212+ is a good and inexpensive one.
try finding a cheaper case, the 800D is HUGE and great if you are going to watercool your system, but other than that it is not really worth it for the price. I would check out the Fractal Design Arc Midi http://www.dabs.ie/products/fractal-design-arc-midi-tow... or the Define R3. I would look for something less than 100.
with those savings looking into an SSD...Crucial m4 and OCZ Vertex 3 are good SSDs. You only need 60/64GB as your windows boot drive but if you can get 120/128GB
Sure, ya can spend another $500 later and get a 2nd 580 .... but that just gives ya 10% more fps than the two 560's .... and the 560's can be OC'd to 30% over their reference speed.....of course every card has different limits
Drop the tall, toothy heat sinks on the RAM....The only cooling effect of these big coolers is that they "look cool". While they served a purpose (when they were effective) w/ DDR2, they are absolutely useless on DDR3.
At more than 2" tall in certain areas the Corsair Vengeance could pose a problem for users like me who use large coolers such as the Scythe Mugen 2. I was able to use the Corsair Vengeance only after I mounted the fan on my cooler on the backside. Size is definitely a concern with heat spreaders of this size and therefore I encourage users to check that they will have enough space under their heatsinks before purchasing the Corsair Vengeance kit.
The problem I have with the Corsair Vengeance is the same I have with many kits of RAM on the market. Companies insist on putting large coolers on their RAM and it limits the choice in CPU heatsinks that can be used within users system. DDR3 does not require these elaborate coolers with its lower voltages which translate to lower temperatures then RAM saw during the DDR, and DDR2 era. Corsair is correcting this with low profile versions of its Vengeance line but ultimately I would like to see the average size of coolers drop instead of having to look for specific low profile versions of a memory line.