The game looked terrible on my 8800GT which defaulted to 'Low' settings, so I bought a new 560 2 gig video card, cranked everything up... and it still looks pretty bad.

But, the worst element is the whole screen flickering once I got outdoors, common problem?, known workarounds? didn't see any relevant threads on the first few pages.

I have the exact same problem. I am running 2 radeon hd 6870s cross-fired and the sky flickers so much it is un-playable! Just started doing it recently. Also, the brightness randomly washes out most everything.

I tried it without crossfire enabled and the sky flickering went away, but the shadows now flicker.