Well CoD doesn't require much in terms of power, and from what I'm being hinted at Ghost won't be that different.
A 4670k, couple of 760s, Corsair HX750, an SSD, nice ASRock Z87 and you're good to go really. My buddy has 2 2GB 680s running 1080p Surround. He has some trouble in certain games due to VRAM so I suggest getting the 4GB cards. If you have a budget, I can make you a build with a location or etailer to purchase from.