This has been discussed numerous times, but as you're new, you wouldn't have heard this. Anyway, this was the general outcome:
NWA are likely to replace the DC-10-40 with the 757-300, although a member of the 767 family could be used.
The DC-10-30 will likely be replaced by the 767-400, although NWA could decide to pass over the 767 family completely, opting instead for the 777-200ER, which would be a stepping stone to the 777-300ER to replace the classic 747s in service with them
Alternatively, NWA could go to Airbus, and order the A330-200. This has been touted as very likely by some people. An announcement is expected in the 1st Quarter of 2001, i.e. any time from now to the begining of April. Probably will come in late january or early february if you ask me. They will definietely look closely at their alliance partner KLM's fleet plans, and could well try and match them. Then again, they could do their complete own thing.
So, thats about as much as can be said for certain, its really no use speculating as none of us run NWA, so we best sit tight and wait for an announcement. Meanwhile, this topic has already been beaten to death, and then some.
"So powerful is the light of unity that it can illuminate the whole earth." - Bahá'u'lláh