What would it be? If you asked me this question a year or two ago, I certainly wouldn't have thought of moonkins and trees! Certainly a bird form would have popped into my mind, but other than that, I might have also thought of keepers of the grove, dryads, and possibly some sort of tauren equivalent (maybe something like a Liontaur!)
A new expansion is coming up, along with new talents and new abilities for the druid class. Who's to say one of them isn't a new form of some sort? Speaking both from a practical standpoint and also based on your wildest dreams (or nightmares), what sort of forms do you hope druids could learn in the future?