For the games you listed, I'd go for a GTX 570, because though the GTX 570 and HD 6970 run neck and neck at that resolution, the HD 6970 takes a bigger hit when Tessellation and Anti-aliasing is enabled in some games.The GTX 570 is also 20 bucks cheaper than the HD 6970.
Good point. The only thing stopping me from going that route right now is the fact that the only thing stopping me from using eyefinity is the lack of space at the moment. Also my motherboard doesn't support SLI.
It's almost come down to something as simple as "my color scheme is red and black, so I'm going with an AMD card" type thing.
Well I'm running 3 Samsung 21" LCD's through DVI inputs. Active single link display port to DVI adapters are about $30. It does take up quite some space but it is worth it. If you might have space within the next couple months or whatever you should consider it. I didn't think I was going to be able to make it work at first either. Being able to see inside the entire car in Dirt 2 is pretty amazing stuff.
Depending on the monitor stand you can also run in portrait mode and have it take up less horizontal space.
Go for the HD 6970 if you want Eyefinity, or get the GTX 570 if you want to save 20 bucks, which will give you the same performance as the HD 6970 with a single monitor, but is better in games employing DX 11 Tessellation.
I know it's very appealing to go for the new shiny exciting product, but 5850cf will provide you with signficantly higher FPS at 1920x1080. Guru3d puts together very comprehensive benchmarks (though I do like Tom's reviews better the comparison sections aren't always as thorough imo)- here is an example of the FPS these setups provide in DiRT 2 at 1920x1200 [edit: scroll down a bit after clicking the links for the comparison sections]:
So you can pick up a 2nd 5850 for about $180 bucks (which I just did about a month ago in a similar situation- I already had a 5850) or you can get a newer shinier card for $350/380 that is going to give you 20% less performance. If you are considering doubling up on the 570/6970 in the future, that changes your picture a little, but as far as the most sensible option right now the 5850cf is your winner.