I feel the 6800 series was a stop gap card.The 6870 was not near as good as the old workhorse 5870.
The 6900 series is better but has the blue line problem.From the pictures I have seen it is not a show stopper.
I thought they had fixed the problem with one of the patches and then it reappeared with another patch.So I am not sure it is a driver problem.With all the people filling out forms to Amd I think they are at least aware of the problem even if our niche is too small to worry about.
Maybe the 7800 series or the expensive 7900 series.
At the moment the more video memory the better.That may change when the new patch arrives.Nvidia has a 4 gig GTX 680 coming.
http://www.hardwaresecrets.com/article/131