Alright, sticking with the i5 than.
Wow, that GTX 570/580 is good looking card, but pricey. I used to be an ATI man, but by the looks of it nvidia is the top dog now.
If you want ATI look at the 6890 or 6970/90, generally ATI is significantly cheaper, but the Nvidia cards are 256bit and 320bit cards and potent.
DX 11 will reduce the processor load on video rendering so GPU will reign again in overall performance, but you want a card that suits that processor, beasts and beasts go well. Just hang around for a while until a good 570ti drops or maybe you have a little extra pocket cash to pamper yourself with a 580.
I understand your position with budget hence why at this point I am step upgrading;
i3 2105
GA P67A UD3R Motherboard
8 (2*4) GSkill Ripjaws
I will keep my Chassis with Corsair VX450w PSU and fans, as well as stick with my 8800GTS temporarily. the P67 is heavily OC bar the fact the CPU is locked, but I am only doing this for 16-20months and seeing how the 2600k or the Ivy Bridges play out. I am looking at a 580ti at the end of the year.