To really help you, we need to know what you're planning on doing with the computer and a budget. Follow the guidelines from the link in my signature to make sure we get all the info we need.
Couple of additional thoughts:
Case: The HAF 922 is cheaper and almost as big. It would be a good idea to downgrade slightly to save a little cash.
GPU: Don't buy a second one. The new DirectX 11 cards (ATI's 5xxx series and nVidia's upcoming Fermi) have drastically changed the GPU landscape. Buying anything less is not a good idea. Go ahead and use the one you have until you don't get the performance you need.
HSF: Switch to the Coolermaster Hyper 212. It's more than half the price of the one you picked and is one of the very best.
HDD: It might be worth it to go ahead and buy a new HDD. There have been big changes from older drives, and you will see a noticeable speed increase. They're also very cheap. The best drive right now is the Samsung Spinpoint F3 500 GB.
EDIT: Forgot to mention that that heatsink doesn't have any fans. You'll need to buy one to make it work. It also weighs almost 2 pounds...
For gaming, you don't need 12 GB. You don't even need 6 GB, but I wouldn't go lower than that for an i7 build.
Now, here's the thing with a gaming build. The i5-750 is just as good as the i7, but the base build is easily $300 (US) less. So I would go with an i5 and buy an awesome GPU. Here's what I recommend:
Mobo: Asus P7P55D-E Pro
RAM: Cheapest 2x2 GB of 1600 mhz CAS Latency 7 sticks you can find
PSU: 850W. Stick to Corsair, Antec Earthwatts, FSP and SeaSonic.
That should be fairly cheap. It's usually about $600 US.
A quick note on SLI: Right now, ATI is a much better option for GPU. ATI's new 5xxx line is absolutely destroying nVidia. This will continue at least until nVidia releases Fermi, and I expect it to continue after that. Indications of Fermi's actual performance are non-existent, except that the card runs very hot. To me, that shows that nVidia had to mess around to make the card compete with ATI, which makes ATI more powerful. However, we'll have to see.
Instead of buying 2 older, less powerful nVidia cards, you really should buy 1 awesome ATI card. I believe that you might be able to fit the HD 5970 in your budget. That is the single most powerful card ever made. You should never need to Crossfire it.
The reason I don't recommend a dual card solution is that you lose an upgrade path. Down the line, when the GPUs stop performing to the highest level, your only choice is to shell out a lot of money for a new card. If you go with a single, very powerful card (right now that's the HD 5870 or 5970), you will be able to stick in a cheap card later and get huge performance gains.
On that site, two PSUs that are cheaper than the Antec Signature and will still be good enough are the Corsair 850 TX and HX. So if you need to free up some money for other components that would be one area where you could spend less.
I agree with pretty much everything MadAdmiral said.