So right now I can buy a 260 for 366$ with taxes and shipping from NCIX.com. I looked at the 280 and it is like 300$ more, and I do not want to spend that. Recently I bought a Samsung T260 26inch monitor, from my old 19 inch. Now I notice my 8800gts 512 is lagging behind, a bit and I need a good affordable boost in FPS, so 260 would be key for that fix. Problem is I have a 600watt PSU, I'll just tell you my system specs, as of now. Would I be able to run a 260 on this system if I took out the 8800gts 512?
Well, you have a 780i motherboard, so have you thought about just adding another 8800GT to run them in SLi? Certainly would be cheaper . There are some cases where SLi doesn't scale well or could provide you with lower minimum framerates, but on the whole two 8800 GTs in SLi would be faster than a single 260.