You actually have a 6850 listed as I now have noticed. I would prefer the 7770 at that price, as the lower power draw and newer architecture is a plus in certain games. They go hand in hand in benchmarks though:
I just looked at your case though, and if you're running an Intel in there, it would be awkward. The G850 and the 945 should have similar performance, but the 945 runs hottter and uses more power. Your call. The Intel route is going to be cheaper at the moment.
Hmm your right guess I'll switch to a different case. Plus the motherbaord you have there is cheaper but supports more and faster memory and with an extra $35 in my pocket I might go for the Sapphire Radeon 7850 thanks a ton.
Changes have been applied.
Current price 548.66 just need a good deal on an HD and I'm there.
Overall with my build you'll get a 7850, good enough for most games at 1080P with adjustments to settings. A better CPU and although it is a smaller PSU, for now it will be good enough and save you money. If you want to Crossfire later, I suggest doing a large scale upgrade with the CPU, MB and PSU.