The favorite topic again, what will NW chose for their DC-10 replacement? Only yesterday I wasn't going to make any predictions, but it seems more likely that they go with the 777. Not the -100 (Boeing is not going to build it), but the -200ER/LR. The 777 is a real money-maker for the airlines and a favorite with the passengers. Look at Air France - they have just exercised 4 more options for the 772ER, bringing their total to 23! For an airline that operates both the 777 and the A340 this speaks volumes.
As for NW, they are looking to make a major fleet decision which will cover not only the -10s, but also the 742s. So the plane they chose for replacement should also have trans-pacific range. So if they chose Airbus, they need both the A330 (for domestic runs and Europe) and A340 (for Asia). The commonality issue is not that big of a factor, since whatever plane they chose, they will need >50, so it will justify the introduction of a different type.
Why I think they will go Boeing? They have already expressed interest in the 777-100, which as a launch customer they could have got very cheap. It looks to me they have made up their mind, but are trying to get a better deal from Boeing.