what resolution and what games? what are your other system specs? If a higher resolution, keep in mind you may need more than the options given, where the 660 would probably be weaker due to lack of memory bandwidth. For higher resolutions, the 670 or 7950 would be a better solution.
If you are at a moderate resolution, such as 1920x1080 or 1920x1200, the mentioned should be fine, depending on the games and settings.
4930k @ 4.1 GHz under corsair H100i
R9 290 crossfire 2x Sapphire Tri X | Seasonic 1250 Gold
16GB Corsair Vengeance on Gigabyte X79-UP4
HP ZR30W | Haf X | Logitech G110 + G500
850 EVO 500 GB + 2TB WD Black