Hi there! The first thing that comes to mind is the Rampage motherboard. for $180 less, you can get the P8Z68-V LX and still get everything you are getting with this build except the Audio. You can also get the P8Z68-V LGA for $50 more and have audio even better than the rampage and an extra PCI-E slot to add another GPU for SLI/CF. Judging from the size of your PSU I reckon you are planning just that.
Second thing is memory. 1600hz CL9 8GB kits are half the price of the 2133hz kits and do not compromise performance in real world applications. That is a mere $40 saving.
How much are you paying for the WD Caviar Black? Can you skip it now and buy it in the summer when production and prices go back to normal?
I can't tell you to skip the Corsair AX gold as it is a phenomenal PSU for the price. However if you are going to use just one Video card, then I would not get more than 650W.
DAS is the best keyboard ever made and it's money well spent. Don't forget to get the WASD rubber set.
WASD Key Set With Inscriptions : Accessories
Case wise if I was on a tight budget I'd get the rosewill Blackhawk. It's not a looker nor is it the easiest to assemble, but it's cheaper, more quite and most importantly, aces the HAF series in aircooling the GPU(s). Again IF I was doing it because no two can agree on the same case.
Saved enough money? Now get ready to spend it on an HD7970. Don't waste your time on anything else. Nvidia's Kepler will come out stronger but that is a few months away. Last thing is if you don't want to puncture your eardrums, stay away from the Z506. get the Z906 or a quality headset.