If like me you are limited to using AGP cards, then I would go for the GeForce 6800GS/XT.
(If you can still find one!). I only changed to a 7900GS recently because I got one for a very good price!
The 7900 is faster, but has caused me some driver problems, which I have now resolved by using nHancer. - But I was very pleased with the 6800 with 94.24 drivers. With the 6800, and by setting the
'Transparency antialiasing' for
'Supersampling', in place of
'Off'. - I was also able to get rid of that one-pixel-line!
The good news....
After further experimentation with
nHancer, I have now been able to get rid of the one-pixel-line with the drivers for the 7900GS ! ...