Originally Posted by
Optinium
Well I play WoW and Civ V to and I use dual GTX580's and I can tell you that a single GTX580 for either game is overkill.
There are cheaper cards available which will run the games flawlessly at most resolutions(and probably Diablo 3 to when it's available). A card I would advise for good price/performance is the ATi 1gb 6850 or the 1gb nVidia 560Ti.
When some people say 'wait for the 6xx or 7xxx series' this could be a good idea, but to take full advantage of these future boards you might need a new CPU, Motherboard, PSU etc... which basically means a new PC, is that an option?