I'm looking to play current and upcoming titles, May get BF3, Skyrim...looking into the new COD game. I'm only using 1 Acer H243H 1080p 24 inch monitor and don't care to overpay. I would like to get a stable 60 fps on the highest settings with my current setup if possible. My personal preference is the Galaxy 670 right now.
It's hard to recommend something without knowing how much your are willing to spend. There is no such thing as a "best GPU", only "best GPU for the price". Tom's has a monthly article on the subject, so maybe scan through it to get a better idea.