Best Duo Class for a Druid?

[Messianic]

I think Magician would be really effective outdoors with an air/water/fire pet, or indoors with earth, although maybe not quite as effective outdoors as a necro.

It's helpful to think of a mage pet as kind of a really powerful dot that has capital cost but no maintenance cost (aside from maintaining burnout, i forget its duration or even if it has one). Druid snare, dot, pet follows behind and beats the tar out of the mob...

Indoors I think fighting undead as druid/nec would be pretty incredible. Necro = undead slow + dots + druid dots. Super efficient.