Are you playing on TLP or live? As someone else who only previously played EQ to get a necromancer to the 40s I found live overwhelming and decided to start on Oakwynd TLP.
I did a war/cleric/enchanter/mage/bard/druid combo. My only regrets are I wish I started with a shadowknight or paladin instead for much better snap aggro and aoe aggro.
I'll outline the reasoning behind all my choices and why I think its the ideal first-group on a new TLP:
Warrior:
I want to main tank raid content/etc and I've read conflicting reports on if SKs can main tank classic-PoP or if you need a warrior. Looking back I think I wish I did a SK first and leveled up a warrior later on. I had a lot of threat issues until hitting level 20ish getting provoke and wulfenite augmentations - two out of era things that are silently left in that help a crap ton with threat. I haven't played a SK yet but I've seen SKs tank really well when I was grouping on the Quarm emulator and other stuff that brought me back to EQ/TLPs.
Cleric:
They are the best and most mana efficient healers by far, getting heals 4-5 levels sooner than the other 2 healer classes. Getting complete heal. If I want to run my own raid group you need at mininum 3-5 clerics to run a 4-2 second complete heal chain. More clerics past that = mana breaks and longevity on a CH chain. Their single target stuns are a god send too in having a charm break for my enchanter.
Enchanter:
Charm nuff said. Huge insane dps doing it all as a group. I read by Gates of Discord/Omens they get hella nerfed but for now I'm really enjoying it. In addition to charm - mez and aoe mez for insane crowd control. Mana buffs too for casters/etc. Haste spells are juicy. Due to haste caps you can be haste capped for really cheap 22% haste gloves.
But wait, that is not all either! Their single target slows makes the scariest named mobs be pushovers. I love having an enchanter/slower in my group.
Mage:
Call of the Hero at 55 lets you easily summon the rest of your group. Unfortunately on TLP there can be a lot of crowded dungeons and 6 toons on /follow draws unwanted attention and train attempts sadly. Probably not an issue at all on live, but definitely worth mentioning on TLP. Post 55 zone in with your 6 box so you're more likely to get a new pickzone open up. If you don't have the zone to yourself and its crowded with no good picks, then invis mage scout lets you see if any camps are open (rarely people stop answering
/ooc camp check sadly) and if so, easy way to get your group there.
Being able to create mod rods for your casters are super nice as well.
Bard:
Their damage shields get insane and are just as strong as a druid or mage's, for the entire group to boot. Amplification and vex thal gear affects their DS, amplification alone = same numbers as an equivalent level mage.
They also get an 45% aoe slow at level 20 in classic. Shamans don't get their aoe slow until 58 and Kunark. This is hugeeee and way underrated by everyone, and why I love enchanter/bard combo. Sure its not 70%+ but it's saved some really bad pulls on me where I had 8+ mobs all beating down, pop slow, boom enchanter gets off their aoe mez.
Sure, this aoe slow overlaps with the enchanter. However you'll be dead with the cast time and recast time for the enchanter to single target slow 8+ mobs. Sure, we can be more ideal and say in a bad pull enchanter gets aoe mez off first and then can spend time casting a longer single target mez on every mob, then slow them, etc, etc. Reality though is you'll get a ton of resists with mez and aoe mez if you're trying to level fast pulling yellows/reds.
Then mezzing is easy to do with MacroQuest but tough and huge task-loading if you obey truebox rules on TLP which is why its really important to us to know if you want to play TLP or Live and your other goals. On TLP I love having my bard constantly doing AE slow, it picks it up quick - I have a melody where its my first song I hit as soon as mobs enter camp, and quite frankly even through the 50s the aoe slow itself without mez was strong enough to trivalize most encounters, and helped a crap ton with aoe mez. AOE slow = insane train protection too. Synergy!
But wait, there's more! Regen songs are OP! Same with magic resist buffs! Get a good drum and in your 30s your health regen will sing for 15 hp/tick, just as good as giving every character a fungi tunic! Then there is mana regen song which can easily be 5-8 mana regen a tick. That doesn't sound like much but I made a spreadsheet of my mage's pet damage per hour, and cleric, druid, mage, and enchanter's nuke damage per mana. If EVERYONE is nuking, yes, including the cleric, this mana regen over an hour is equivalent in damage per mana to having an equivalent level mage plus their pet in the group, just from ONE song. I don't know how it'll scale past 60+ but for one song - I was impressed.
Yes, everyone has to nuke. I've found in doing so that with everyone nuking mobs die in 1, sometimes 2 salvos, and the only time the cleric ever has to heal is really bad 8+ mobs pulled up, named mobs, and deep red overcon mobs - at 38 I accidentally fought level 50 mobs in the hole with this comp as I didn't know jumping in the hole was not what people considered to be the zone in.
Oh I almost forgot the speed song too, with a good drum its faster than mount speed. I love having my bard. I prefer running my team without mounts too, mount collision is weird. For cheap mounts I popped buying every box the house of thule pack that gives each account 999 claims for 2 diff mounts available at luclin launch. Those mounts are equal speed to the 105k plat baz mounts.
Then group wide double invis = really nice train protection too. If you see someone intentionally training and they don't have aggro yet = invis up.
Druid:
Finally the druid... I'd say this feels to be the least loved class here. However I love my druid and my main was a druid on Quarm before hopping over to Oakwynd. I treat my druid as primary DPS and backup healing - like I feel comfortable saving 20-30% mana for backup healing.
Early TLP until Plane of Knowledge unlocks you need ports. Even with PoK ports are still a nice time saving feature to get closer to content faster. I love being able to port -> lesser succor -> zone in 5 minutes.
Speaking of succor - it's saved my team numerous times learning how to multibox EQ. It's saved me from intentional trains by jealous spiteful players. I really think a dru/wiz for a succor class feels mandatory for TLP until you're in LDON+ fully instanced missions. I've had a few attempts that people trained 20+ mobs intentionally on my multibox. There is a nice pottery succor clicky item for dru/wiz so you don't even have to mem it. I just succor out and peace out, not one death again thanks to a tanky bard slow grabbing initial aggro until succor can complete.
Then if you're day-1 TLP for 8-12 weeks of classic only - you may want a 7th or 8th account to be a wizard to port to various planes easily. If I started day 1 TLP I'd 7th-account druid, 8th-account wizard, then those 2 probably be enough to continue on as 24/7 bazaar alts. Even better than finding a parcel npc for your vendor, imagine one of those porting near your dungeon and dropping off something you need. However - if given a choice most people prefer druid ports over wiz ports. Druid ports seem to be more relevant for most people - zone into lavastorm vs nektulos forest for instance. Only downside with druid ports if you have evil people in your composition = chance for them to get attacked by other npc druids. Be sure to invis evil players. So day-1 TLP if money/time is no object get both druid and wiz, druid first to help plevel wiz/new toons, then wiz is the only way into the planes easily.
Speaking of ports, I assign my druid to be my looter and I funnel all loot to that character on my 6 box team. Since he can self teleport/port anywhere I don't mind binding him outside the dungeon. I can origin back and sell, then gate back easily. Then he can port to nexus/wherever the team is just as easily. Even though from what I've read that traveling becomes easier in later expansions it still sounds nice. Given the really nice looting - I'd always want a porter class for TLPs for my 6th. I don't know how much vendor trash you get live if it makes a difference though.
Then having a thorns class is super nice for future planned power leveling. Sure you can bring in mage + cleric, but that's 2 boxes/2 characters/more complex. Druid = powerleveling in a box. Bind outside the dungeon, cast thorns + regen buffs on everyone in your new 6-box crew, have them go to town. When you're done with that dungeon port 5, come back to your bind spot, port the 6th, off you go.
You can also try reverse powerleveling with this setup too, cleric + druid + bard will give you the max damage shield, heals, and a good aggro tank with either the cleric or druid constantly healing + insane regen. Have an aoe bard/aoe caster in the 6 man group to do 1 point of damage, and the rest of thorns damage is unassigned, so they get the credit/xp/and loot for killing, with druid being a nice backup healer if the cleric gets interrupted/stunned doing this method.
Then druids have a ton of other insane buffs - protection of the glades/cabbage to give hp/ac/mana regen buffs. I think cleric symbol + cleric ac buff + skin buff gives the highest HP and AC combo in the game too. Spirit of wolf buffs too! I love having SoW even with bard speed - sometimes selos drops off, etc. Their regen buffs are outstanding too - stacks on top of bard regen and pack chloroplast = fungi for everyone as well.
Then the druid has a pretty mean fire resist + AC debuff from the Breath of Ro line that stacks with tash and malo. It super charges my mage's dps. If you ever want to raid you'll definitely want at least one druid in your group.
I'm not sure about future expansions but at least for the next 1-2 years on Oakwynd I can definitely see me continuing on with my druid, and if I decide to replace the druid, the druid will always be a "7th account" that is worth having alone just for the buffs/utility/etc they provide.
Charming - oh wait, I almost forgot this, but druids can charm animals too, and in places that have animals = same dps as an enchanter. However seeing charming side by side with a druid and enchanter on identically level mobs and identically leveled debuffs - the druid charm definitely breaks more often. That's because code wise if the enchanted mob fails its level and magic resist checks, it gets an additional charisma check to see if it remains charmed. The druid doesn't get that check, so they do break charm more often. It's also time consuming if you're having to deal with 2 charm breaks at once. It's something to keep in mind but definitely enchanter charms > druid charms, but it can be a huge component if you happen to run across charmable monsters.
I wouldn't go out of my way to explicitly only dungeon in places that have druid charms available, but definitely use druid charms if they're available!
Additional accounts -
I spoke a lot about additional accounts and if you have the time and money I think it's always worth having these classes no matter what to buff other toons:
Druid/Wiz - all my reasons above.
Enchanter - KEI/mana regen buffs are really nice even if your only caster is a cleric or shaman.
Shaman - Huge single stat buffs/etc are really amazed. It's like getting several slots of gear for free.
Beastlord - not sure about melee but beastcrack is really nice for more mana regen for casters and stacks with potions, enchanter buff, druid buff, and bard song.
Mage - even if you're doing a 6 box comp of all melee, no mage, running one on a separate account just for CoTH seems worth it to me, group up 5, coth them in, group 6th, done. I can always see keeping a mage around. I don't think it works for LDON stuff though.
Cleric (TLP only) - just keeping a cleric around for a 96% rez is worth it even if you decide to later do SK/SHM/Bard + 3x melee dps. Shaman/druids don't get 90% rez until Omens of War. If you're playing live I don't currently see any reason to keep this account active all the time.
Finally - remember to have fun and that there is no perfect or ideal comp! For instance at first glance someone would think 3x enchanters + 3 wizards wouldn't be an ideal comp but it sounds hella fun to me. 2 enchanters can perma aoe stun mobs with a 6s stun 12s recast time spell, later turning it into 8s/12 recast. The third adds a margin of safety for resists/geting off sync. Then 3 wiz could aoe stuff down. Add 3 charms to the mix = chaos and insanity. Someone could train the whole zone on me with such a comp and that would be a "thanks for pulling" for me for real.
3x+ enchanters is the backbone for any aoe powerleveling if you want to exp up a lot of 60s to do your own raids too.