1GB or 2GB GPU for COD

[braveheartm]

Hello guys,

I'm planning to buy myself a new GPU for running COD on a 1680x1050 screen.
My options are GTX 560 TI with 1GB or 2GB memory. This would be an easy choice since at this resolution the games I play don't require more than 1 GB of vram, however I'm not sure about COD.
Should I go with 2GB or 1GB for vram? What am I loosing if I go with only 1 GB?

P.S. the 2GB version has a higher price (+50 eur).