For all of you that have torrented/bought the game, and are having issues getting decent fps, turn the graphics up to their highest level, and just reduce the draw distance, shadows and the other couple of options.
It may sound stupid, but the game is designed to run better on higher settings, so max that shit out, and you will find your fps get much better.
If you have a new GFX card, something really high end (4870, 4780x2, GTX280/260, 9800GX2) and you find your fps are better but the game hits low fps every 30 seconds, try o/cing your cpu to a much higher clockspeed, and you will find you will have much better gameplay, and i'm talking about 40-50fps constant!!!