[Classic] Good farming team?

[Apatheist]

If you want to farm the place to do it is dungeons and raid trash. You get the best drop rates on everything, more stuff to DE and in some cases chances for some pretty nice BoE gear (ZG trash, Dire Maul.) One of the primary benefits of boxing is being able to farm content by yourself that is usually only accessible to groups. It doesn't make sense to farm locations that can be done solo as a boxer.

With that in mind, optimal "farming" teams will be the same as the dungeon teams. I would think any tank with sound AE threat (paladin or druid) any healer and a combination of mages and warlocks.

You can reach the same conclusion through a process of elimination.

1. Hunters could work but are too micro intensive to box effectively, are heavily limited by their dead zone and have limited AE. The upside is that hunter pets actually make good dungeon tanks. An owl with max rank screech generates reasonable AE threat.
2. Melee classes are heavily gear dependent and subject to the availability of IWT.
3. Shadow priests, druids and elemental shamans are all low DPS, lack AE damage and run out of mana very quickly.

If you're going for optimal efficacy, mages and warlocks are really the only choice IMO.

Something like:
druid, shaman, mage, mage, warlock.
paladin, priest, mage, mage, warlock.
etc.

Covers all the decurse options (curse, magic, disease, poison) and gives you most of the useful buffs.