GPU: Gigabyte GeForce GTX550 TI OC 1GB GDDR5 ~164$
Is that motherboard ok? 'Cause i didn't found anything on that motherboard. I would prefer Gigabyte or MSI over Asus.
And the RAM is really cheap (at least here, maybe it turns out a little expensive with the conversion), but the CL9 and the 1.65V concerns me, and the only 1.5V i can find is from G.Skill, either 2x2GB or 2x4GB.
I prefer 1x4GB now, and have the option to buy another in the future, but i only can find that Kingston.
In regard to the GPU, i know that maybe the HD6790 would be better, but I've had some traumatic experiences with ATI, especially in games, so I'd rather have Nvidia.
get the 2 x 2GB RAM, most MoBo's are dual channel, allowing for best performace with 2 sticks of ram. And for Intel, you need RAM that is 1.5V, any higher and you risk damaging your system. As for the cas latency, the lower the better.