I'm thinking about a GTX 770 so I just wanted to know what you required to get over 1 fps with ultra shaders like I do :P
Fps for optimized soft shadows with a GTX 770 is 60, depending on location and map size.
For ultra shaders, its about 20. But no one runs ultra shaders for gameplay anyway, so a GTX 770 is fine for screenshots.
I own a GTX 770, and it runs beautifully, the only games i can't max out without 60 fps are Ubisoft games and Crytek games.
Bf4/Bf3- 70 fps
Watch dogs (The Worse Mod) - 40 fps (Terribly optimized game)
Most Open GL games - 300 fps
Blockland Default - 200 fps (small map) 60 fps (larger map)
AC4 - 40 fps
Crysis 3 - 30 fps (Ultra settings, very graphics heavy)
Hopefully this generalizes the power of a 770. These are all running at 1080p with an I7 4770k
If you can spend more, get a GTX 780ti. Or wait until the maxwell GTX 800's come out.