What profession should a druid take?
There are many professions out there. Many reasons to take this one or that one. The biggest benifite of a profession are those that can improve your character directly. Most of these include BOP items or items only usable within your profession. Leatherworking, engineering, alchemy, enchanting and jewelcrafting are all professions I would suggest.
obviously leatherworking gives you a lot of equipment to wear. As a druid you will have many sets of armor. being able to make it yourself can save you a lot of headache. Drums come in handy as a usable buff/fear while in combat, now usable in forms.
I dont know a whole lot about engineering, but I do know it has some nice items that you cant use otherwise. There are a set of goggles that are quite popular and can compete with many of the other helms available. There are bombs and odd trinkets that you could use (but as far as I know not in any forms). you can make jumper cables to try to offset our only 1 res per 20m limit. you can make repair bots. There is a new extractor thing that lets you pull motes of water/shadow/air similar to another gathering profession on it's own.
All in all it has some nice tricks.
Most alchemy stuff can be traded to other characters. But there is worth mentioning a trinket you can equip which increases the amount of health/mana you get back from a potion as well as giving you a deacent stat bonus. Also worth mentioning are mad alchemist potions, these potions require alchemy to use, restore mana and health, and sometimes give you a random flask bonus.
there are few enchants that you can only cast on your own items. right now these consist of ring enchants raising your stats/melee damage/spell damage or healing. The biggest reason I see taking enchanting though is for disenchanting. Yes lots of clothies generally take it and can shard for you in an instance or raid, but clothies cant go with you on stealth runs just to disenchant shards.
Jewelcrafting has many trinkets and jewelery that is BOP. Esp useful while leveling as they are available long before normal trinkets are. Also in the end game there are gem cuts that are BOP.
Which ever profession you chose just have fun with it. There really is no best answer. just make sure whatever you are doing that you enjoy it.