i assume your monitor will have 1980x1080 as a native resolution. for the game that you're going to play GTX560 Ti will eat it for breakfast (even the upcoming modern warfare 3). as for the card i would get the MIS one or the Asus one because of the cooler being used. i don't know about the Palit one but for sure you're not going to need that massive VRAM comes with the card unless you want to play on higher resolution or multi monitor setup.
Why not get the Hawk version of he MSI 560 Ti? I have one and it's killing everything i throw at it, it has better cooling on the card which means you can overclock more, plus I believe their cheaper on newegg right now. I use it for Media conversion and crysis 2 gaming.