I just upgraded my machine to Debian unstable which also includes X.Org 7.1. After reinstalling the nvidia driver I used before (8774) X started up without any error messages, but unfortunately the card does not display an image.
I then updated the driver to 9746 which gives the same result.
With X.Org 6.8 everything worked fine, the xorg.conf file only experienced very minor changes (adjusting the font path, removing unrecognized options from the nvidia driver).
Another curiosity is that xrandr displays no resolution for the nvidia screen, but for the screen which is on my other card.
As my nvidia-bug-report.log is too big to attach it, I uploaded it to some webspace of mine: http://www.uliweb.de/nvidia-bug-report.log