Built this Windows 7 system to replace a 2007 iMac with the main focus on using it for gaming. I focused on high airflow while keeping the system fairly quiet. Although currently not over clocking, I used Cooler Master's Hyper 212 Evo on my i5-2500K in case I wanted to in the future while keeping my CPU at a reasonable temperature (idles at about 28°C currently). The HAF 912 case was fantastic and I would recommend it as it comes with two quiet fans and a cool modular interior design, with enough space to house massive graphics cards like mine (with lots of opportunities for cable management, which I only somewhat used). So far my graphics card has been great, running at the standard 915 MHz, and has been practically flawlessly running Skyrim on best quality. I'd recommend this card if you grab it on sale. Start up times with the Vertex 3 SSD are blazing fast, and I would hate to go back to running OS on a HDD now.
On the downside, the cables provided with the OCZ ModXStream Pro are kind of short even for a mid-tower case, making it a little challenging to run the CPU power connector. Also as you can see in the pictures, I am currently forced to run my RAM in side by side slots, since I'm having problems running dual channel (not sure if this is a motherboard issue). I purchased another fan for my case, a Cooler Master Excalibur, which I later removed because I found it too noisy and unnecessary. I'm also using a D-Link DWA-556 PCIe wireless adapter, which has too many flaws for its price, however it is working reasonably after some driver adjustment.
Aside from those few issues, this build is great and I would highly recommend it to anyone looking to build a ~$1000 gaming PC.