I just received my Samsung 8000. Out of the box, the picture has a slight greenish cast to it. Adjusting the red-green balance does not help it.
What are the settings I should play with to address this issue?
without a meter/software, you'll want to toggle between various color temp presets until it disappears or is minimized (probably Warm1 or Warm2... Cool and Standard will be far too blue)
What picture mode is out of the box?
from the comments on the owner's side, and several review sites, I would only use "Standard" and "Movie", both with Warm2 settings.
From all the reports I have seen, the Standard and Movie modes were never too green: Nitra had too much red, and badwilly and myself had too much blue.
There is not much response on this thread. I have seen that you are also on the owner's thread, and as there is more life there, you might get more feedback there.