we got ours end of December and just found this. after adjusting to Food network/TNT/HBO/NatGeo/AnimalPlanet... all in HD on cable... we came to this as our settings. try it and play... let us know what you come up with? can't seem to find any reviews on it with 'optimal' settings.
contrast 90
brightness 50
color 50
tint 0
sharpness 6
color temp = normal
dynamic contrast = off
DNR= on
color enhancement = on
picture format = wide
horizontal = 34
vertical = 14
these numbers seem weird, but it's what looks best to us.