Well... you can get a GPU now but if you can wait till Q1 2014... you will get the next gen AMD/Nvidia GPU's. I suggest waiting only because Nvidia has become greedy imo for this year with the absence of AMD...
A 770 which basically performs about the same as a 680 (just a bit better) also costs as much as a 680 but usually in tradition.. it should cost less than a 680 because it is suppose to be the 680's replacement and a 780 which out performs a 680 should cost as much as a 680 and not about $200 more (give or take $50)
But if you can't wait then I suggest you get either a 770 if you can afford it or a 760... Or if you like AMD which does cost cheaper but doesn't have the performance of the 700 series... I say go with 7870 x2 (you can find them on sale easy) or a single 7950
PC Specs: CPU: 7800X3D || GPU: Strix 4090 || RAM: 32GB DDR5 6000 || Main SSD: WD 2TB SN850
