I've got the reference 6950 board which can be unlocked to the full 6970 shaders (not sure if that's still possible?), was £160 on the MM a couple of months ago although not sure how much the extra shaders really help?
Anyway, I've got a similar system but a slightly higher clocked dual core rather than the quad, I run 1920x1200 on all 3. When I first got the 6950, and for a fair while, I was running everything on full and that was playable everywhere but Spa really, Suzuka was a bit of a hit as well though.
Since then I reduced the shadow level, turned off the higher detail in mirrors, both of which you barely notice, but also dropped the AA to 2x (although using in-game, I believe through the CCC is better but this 'just works'), I don't mind it but it's the only really noticeable change, after this I regularly see 150+ fps and not seen lower than 70fps so far...