It depends on level range. I'd say magician or enchanter depending on your playstyle. The fastest non-pl box duo I've ever had to make it through to 70 was a wizard and an enchanter (a druid would be a safer alternative to the wizard). As long as you know a good place to level that involves non summoning mobs, wiz/enc would be my favorite combination until charm gives out around level 100. I realize that's a biased statement, but to me charm became much less good at 100 due to the lack of dual wield pets aside from grelleth, and then at 105 it just was outmoded as a means of dps. However, if you changed strategies, used 2 caster dps mercs, and tanked with the enchanter, you could have a pretty good group still. The magician/druid in my eyes would be the safer pick, and the enchanter/druid would be the riskier pick, but could yield better rewards if you know what you're doing. If you're looking for a hybrid to pair with a druid, the groupings would all be so different that it almost just depends on what you want. Bards would be better if you want more versatility. Rangers can be very good as well, even though you're doubling up on some abilities like snare but they probably would end up as the best hybrid for tanking (not including sk/pal). Beastlords are very cool but a mage would be better with a druid (especially at higher levels... spell damage and all).
Today now that pet can tank for you , Bst is a very good combo with Druid , but any of the pet class will be good for you ....Pet is tank and can have two DPS mercs, if you can heal good with the Druid , also Bst can heal the pet very good ....Dru/Bst combo is like having a super Shaman Yi Min
So, you could do so many different things. Utility - bard. You'd be relying on pickup tanks/pets or mercs, but you, wiz merc, bard and tank merc could clear a lot of things. Pet class - mage or bst with druid is pretty awesome. Tanks - any of the tanks can make a great partner for a druid who is interested in more than just spamming heals. Hybrids - ranger, zerker or monk can partner w/ a druid, but they're pretty meh. Silkie - you can make a viable group w/ any silkie and mercs.
SK is far and away the best tank partner for dru, as all the caster support activities do wonderful things for them.
Some of my finest EQ memories were experienced with my druid buddy Wulfmann. Not too much a mage and druid cannot handle.
