Best possible GPU(s) for a single monitor? (1920x1080)

[Waffleking]

Hey, Christmas time is getting close, so i'm wondering what card i'm going to give myself to finally "Perfect" my system. Out of all the parts, after building the system, I can safely say the GPU is the weak link.

That's where you blokes come in. I don't want to run anything at (MYXEYES!) resolution, but I DO want to safely run MOST things at 120fps (I don't currently have a monitor capable of it, but eh, ain't no kill like overkill.) at a steady rate if possible. Unstable frame-rates are...Hellish.

I don't understand the whole crossfire thing. but I'd prefer to not do that unless it was both cost effective and outperformed the single card option.

My specs:
MBAsus Sabertooth z77

RAM: Ripjaw (16gb) http://www.newegg.com/Product/Product.aspx?Item=N82E16820231486

GPU: Nvidia GTX 560ti

CPU: Intel i7 3770k 3.5GHz (Ivy bridge- Not overclocked yet.)

No cooling system- Case has a built in one, using default fan for the Intel.

Corsair Graphite Series: White
http://www.corsair.com/pc-cases/graphite-series-pc-case/special-edition-white-graphite-series-600t-mid-tower-case.html

Thanks in advance.

 

[iisfitblud]

This will easily be able to get the performance your looking for. A constant 120 FPS is not really possible at the moment, mainly just due to drivers, but for brilliant 1920x1080 performance the 780 does the job well. But as I say, there are a lot of limiting factors in the FPS, sometime its just the game too.

http://www.scan.co.uk/products/3gb-evga-gtx-780-superclocked-acx-28nm-pcie-30-6008mhz-gddr5-gpu-967mhz-boost-1020mhz-cores-2304