Well I did some tweaking with the in game settings and some research and I was able to get the game to run smoothly at 1680x1050. Most of the settings are currently at high, with the exception of the shader quality, water, and shadows which are at medium. There is some slowdown in sometimes, such as using binoculars and zooming in, but everything else is completely playable and smooth.
I tried it with shaders at high and the game starts to chug. Everything looks even more gorgeous with the shaders at high (lots of bloom effects and the flora looks really impressive), but the game runs at like 10-15 fps with that, versus about 30-40 fps with the shaders at medium. It's a reasonable tradeoff, since the game still looks really good.
I am currently using a Geforce 7900 GTX, AMD Athlon X2 4400+ and 2GB of RAM, for anyone who is interested.