The weapon of choice for a Mage!
There are many different kinds of Staffs, some of which are available for purchase at Port Juno. Others require crafting(Currently elemental staffs cannot be crafted). They each will launch a different projectile, with a different animation. These are usually just the color of the material the staff is made of in some design, with a trail of particles behind it.
All staffs, when looked at in the inventory, all have the same damage value. The damage there is based entirely on the actual melee attack power of the staff, and should not be taken for the actual attack power. In reality, the attack power is based on the mage's mana damage and the material the staff is based on.