Class: Druid

DRUID: (Night Elves, Tauren)
The druid is a shapeshifting hybrid class, and is also one of the most versatile classes in the game. As with every other hybrid, druids need to specialize to be effective in any role. Due to their need to shapeshift to fulfill roles, they can only perform one role at a time. Druids must switch between the different shapes in order to adapt to situations as they come. Druids can serve as 3 different types of character (DPS, Tank, or Healer). They are a jack of all trades but a master of none, when fighting in groups.

SHAPESHIFTING
Bear Form: Level 10
Aquatic Form: Level 14
Cat Form: Level 20
Travel Form: Level 30
Dire Bear Form: Level 40
Moonkin Form: Level 40
Flight Form: Level 63

ARMOUR AND WEAPONS
Druids are able to wear cloth and leather armor only. Druids start out with different weapons depending on race; night elves begin knowing staves and daggers, while tauren begin with staves and one handed maces. Beyond that, druids can learn to fight with:
Staff
One-handed Mace
Two-handed Mace
Dagger
Fist weapon
Polearm
Druids cannot use shields (but in bear form their armor is as high as though they had one), and they cannot dual wield. "Held in off-hand" items can still be used. This leads to druids using either a two-handed weapon, or a 1H + off-hand item.

TALENTS

Druid talents are split into three categories:

•  Balance - Focus on Damage Spells to make the druid an efficient caster damage dealer.
•  Feral Combat - Focus on using the druid forms (Cat Form, Bear Form, Dire Bear Form) in the aspects of tanking (Bear/Dire Bear Form) and melee damage dealing (Cat Form).
•  Restoration - Focus on Healing Spells to make the druid an efficient healer.

It is important to note that each druid talent tree contains some talents which are actually useful if specializing in one of the other trees. For example, some Feral Combat talents modify maximum mana, some Balance talents modify cost of healing spells, while others are helpful for the feral forms. Finally, some Restoration talents give the druid rage/energy when he switches into either Cat or Bear Form.

Good talent calculators can be found here: Official Blizzard site, Wowhead, and ThottBot.