Be careful with that noctua heatsink. They are very tall/heavy so make sure there's enough room in the case and also make sure you mount it correctly and do a CPU Burn in once OS is loaded, as that will harden the Heatsink glue a little and prevent you breaking the motherboard. Trust me, it happens. I learnt from my own mistake when I mounted a full copper heatsink on my CPU.
And Even though APC is a good surge protector brand. I wouldnt suggest cheaping out on it. I would spend a tad more than $13 for my surge protector. Because it is the failsafe in the event of lightning being a bitch.
All in all, not a bad build. Can I ask why you went for 2x 6970's over a GTX590? Generally I find single card builds I have made are more stable with less tearing and have less hassles in the long run. I.e if something fails and trying to fix it. Also Sandy Bridge only supports a single PCIe x16 link coming from the CPU so you should get better performance out of a single card, unless you want to switch to an X58 i7 chipset (920,930,950,980x,990x,etc)
EDIT: Also I believe Intel are bringing out the new Ivy Bridge processor in Q1 2012 and they have a MASSIVE performance increase over the Sandy Bridge architecture. So you might want to wait, you might not.