Staff

General
A staff is a two handed, projectile weapon that can require one of a variety of monk, mesmer, elementalist, necromancer, or ritualist attributes.

Note that the plural of staff is staves, not "staffs".

Staves are the two-handed alternative to the combination of a right-hand Wand and a left-hand Focus Item. The discussion whether a staff or a wand/focus combo is superior is as old as the game itself. Upgrades and modifiers below briefly discusses the differences between staves and wands.

Inherent stats

 * Ranged weapon, with height affecting amount of damage done
 * Minimum damage range: 2-4
 * Maximum damage range: 11-22
 * Damage type: Depends on linked attribute.  Possibilities: Cold, Earth, Fire, Lightning, Chaos, Dark or Light.  (See staff types below for details.)
 * Attack interval: 1.75 seconds
 * Range: Recurve Bow range (~1.2 aggro circle radii); equivalent to standard casting range; not affected by height, unlike bows)
 * Arc size: Small
 * Projectile flight time: ~0.6 seconds at Shortbow range.
 * Energy +3..10
 * Halves skill recharge of spells (Chance: 10-20%)

Staves with an attribute requirement of 0 have been observed with a damage range as high as 7-11 and energy as high as 6.

Upgrades and Modifiers
Staves, unlike wands, always come with an energy bonus included. The max possible energy bonus of all staves is +10, slightly less than a focus, which has +12. This disparity is somewhat offset by the fact that one need not meet the attribute requirement of a staff in order to get the full +10 energy from it whereas with a focus not meeting the requirement will drop the energy down to +3 or +6. Another difference is that staves can be equipped with a magic head (name prefix) and/or wrapping (name suffix) to add extra bonuses to the weapon. Furthermore, a staff may come with a number of non-salvagable magical modifiers (with the coming of Nightfall all modifiers are able to be salvaged except 'Halves Spell recharge' which is sometimes a part of staff itself), just like any other weapon, focus, or shield.

Staves can be upgraded with Adept, Defensive, Hale and Insightful Staff Heads and Staff Wrappings of Defense, Shelter, Warding, Enchanting, Fortitude, Mastery,  and slaying.

Core

 * Monk Staves
 * Holy Staff (Divine Favor): Fire damage
 * Smiting Staff (Smiting Prayers): Light damage
 * Necromancer Staves
 * Accursed Staff (Curses): Dark damage
 * Blood Staff6 (Blood Magic): Dark damage
 * Bone Staff (Death Magic): Cold damage
 * Soul Spire5 (Soul Reaping): Dark damage
 * Mesmer Staves
 * Inscribed Staff (Domination Magic): Chaos damage
 * Jeweled Staff (Illusion Magic): Chaos damage
 * Scrying Glass Staff (Inspiration Magic): Chaos damage
 * Arcane Staff5 (Fast Casting): Chaos damage
 * Elementalist Staves
 * Air Staff (Air Magic): Lightning damage
 * Earth Staff (Earth Magic): Earth damage
 * Fire Staff (Fire Magic): Fire damage
 * Water Staff (Water Magic): Cold damage
 * Ether Staff5 (Energy Storage): Chaos damage
 * Universal Staves1
 * Ghostly Staff
 * Shadow Staff

Prophecies Campaign

 * Necromancer Staves
 * Cruel Staff2 Blood Magic): Dark damage
 * Wicked Staff2 (Curses): Dark damage
 * Universal Staves1
 * Dead Staff
 * Raven Staff

Factions Campaign

 * Monk Staves
 * Divine Staff (Divine Favor): Fire damage
 * Healing Staff3 (Divine Favor): Fire damage
 * Holy Branch (Divine Favor): Fire damage
 * Protective Staff3 (Divine Favor): Fire damage
 * Winged Staff (Smiting Prayers): Light damage
 * Necromancer Staves
 * Dark Tendril Staff (Blood Magic): Dark damage
 * Evil Eye Staff (Curses): Dark damage
 * Wailing Staff (Death Magic): Cold damage
 * Wicked Staff2 (Curses): Cold damage
 * Mesmer Staves
 * Clairvoyant Staff (Domination Magic): Chaos damage
 * Gemstone Staff (Domination Magic): Chaos damage
 * Hypnotic Staff (Illusion Magic): Chaos damage
 * Ritualist Staves
 * Channeling Staff (Channeling Magic): Cold, Earth, Fire or Lightning damage
 * Communing Staff2 (Communing): Dark damage
 * Conjuring Staff (Spawning Power): Cold, Earth, Fire or Lightning damage
 * Eerie Staff (Communing): Cold, Earth, Fire or Lightning damage
 * Restoration Staff4 (Spawning Power): Lightning Damage
 * Spawning Staff2 (Spawning Power): Lightning damage
 * Writhing Staff (unconfirmed) (Restoration Magic):
 * (Universal Staves) (Restoration Magic): Earth and Lightning damage have been confirmed
 * Universal Staves1
 * Amber Staff
 * Bo Staff
 * Celestial Staff
 * Cockatrice Staff
 * Dragon Staff
 * Forbidden Staff
 * Jade Staff
 * Lotus Staff2
 * Outcast Staff
 * Plagueborn Staff
 * Platinum Staff
 * Zodiac Staff

Monk staves

 * Sacred Staff : Fire Damage : Divine Favor
 * Protective Staff : Fire damage : Divine Favor or Protection Prayers

Elementalist staves

 * Pyrewood Staff : Fire damage : Fire Magic
 * Tempest Staff : Lightning damage : Air Magic
 * Tidal Staff : Cold damage : Water Magic

Necromancer staves

 * Boneclaw Staff: Cold damage : Death Magic
 * Spinal Staff : Dark damage : Blood Magic
 * Unholy Staff : Dark damage : Curses

Mesmer staves

 * Ensorcelling Staff : Chaos damage : Domination Magic
 * Hypnotic Staff : Chaos damage : Illusion Magic or various
 * Illusory Staff : Chaos damage : Illusion Magic

Universal staves

 * Staff of the Forgotten
 * Tormented Staff

Unknown attribute staves

 * Portal Staff : These are based on a Variable attribute, with the attribute determining the damage type. In the case of  Portal Staves based on Energy Storage, the damage type appears to be randomly determined.   Cold,  Earth and  Fire Damage types have been observed thus far for Energy Storage based staves.