Well now this 1.9 patch has come along, the game looks a lot better. But it doesn't seem to matter if I'm still running the game with everything on high.
Also, the high res textures up close don't really look that much different either. They look better when everything is further away though. Whatever, I don't get any performance hit from using the high res textures, so it's cool.
I'll be running the game with everything on high, in DX11 mode with my 2500k and 5850. Don't see a reason to get a GTX580 just to run this on any higher graphics settings.