Death knights have three specs available to them - Blood, Frost and Unholy.
Blood focuses on bending corrupted life energies to sustain and attack his foes, sporting a two handed weapon and plate armor this is the Death Knight's tank spec.
Frost masters the runic energies accumulated by death knights and channels it into a bombardment of frost based attacks.
Unholy commands the necrotic diseases available to the death knight and controls undead minions and bolsters a formidable resistance to magic attacks.
All Death Knights use Runes and Runic Power as a resource system, Runes being depleted upon using a regular ability and Runic power being used to fill the time between your Runes recharging.
Druids have three specs available to them - Restoration, Balance and Feral. However in "Mists of Pandaria" the next expansion the feral tank and feral DPS specs are being seperated.
-Restoration uses nature energies to heal allies who are taking damage, focusing on "Heal over Time" spells and utilizing the powerful "Tranquility" cooldown which can heal an entire army in seconds.
-Balance employs a variety of spells powered by lunar and solar energies, by spending a certain amount of time in each "eclipse" they can severely increase the potency of their spells and when outnumbered can call upon stars to fall on their enemies.
-Feral is the only spec in game which has two roles, a player can choose to tank by shapeshifting into a bear or DPS by shifting into a feral cat form.
Naturally all druids are difficult to control due to being able to shift in and out of different forms and is ideal for any player who constantly becomes bored of performing a certain role.
The hunter can choose from Marksmanship, Beast Mastery or Survival.
-Marksmanship emphasizes a hunter's ability to fire devastating ranged attacks with a deadly accuracy.
-Beast Mastery utilizes a hunter's companion to it's fullest and even allows the hunter to tame exotic creatures from other worlds.
-Survival increases the damage/utility of a hunter's traps and allows them to fire explosives from range.
Hunters are capable of soloing things which other players could only do in a group through using their pets as the tank.
A mage can choose to spec either Arcane, Fire or Frost.
-Arcane uses the very essence of magic to destroy anyone who is dumb enough to let you get 4 stacks of arcane blast.
-Frost controls and cripples enemies and can line up powerful "shatter" combinations which cause large amounts of burst damage.
-Fire uses "Damage over Time" spells and can combine them into one powerful DoT and spread it amongst their enemies.
Mages are a pure DPS class and as such have high utility and probably the best AoE in the game at the minute.
A paladin is the second most versile class, being able to melee DPS, heal and tank through their Retribution, Holy and Protection specs.
-Retribution harnesses the holy light to correct any injustices in Azeroth, retribution has the highest burst DPS in the game.
-Holy uses the holy light to heal allies, holy specced paladins are also very useful because of their powerful cooldowns.
-Protection calls upon the holy light and guardians of ancient kings to protect themselves and their allies.
Paladins have a high skill ceiling, however it is not hard to play one decently.
Priests can heal or DPS, they do however have a unique shield based healing spec.
-Discipline utilizes shields to protect enemies and powerful buffs to help heal or damage an enemy.
-Holy uses the holy light to heal allies, holy specced priests have a powerful raid cooldown similar to tranquility.
-Shadow uses twisted energies and diseases to distort an enemies thoughts and can even mind control enemies.
Priests are a very enjoyable class however their damage dealing is limited to DoTs so it may not be the best for people who enjoy fast action.
Rogues are a pure damage dealing class, however they rival mages in the art of controlling an enemy and bursting them down.
-Subtlety uses stealth, stuns and bleeds to hide from, disable and silence any victims while also bursting them down rapidly.
-Assasination specializes in poisoning and tearing their enemies to shreds using daggers.
-Combat enhances a rogues already formidable armory of combat skills, allowing them to shift between enemies extremely quick and strike two enemies at once.
Rogues are extremely fun to play and are not hindered by playing solo as they can control up to 3 people at once without a problem.
Shamans can heal, melee DPS or ranged DPS and are a very well designed hybrid.
-Restoration uses the spirits of water and earth to bolster and heal allies.
-Enhancement uses the spirits of wind, fire and lightning to quickly deal high damage and can interrupt with the lowest cooldown in the game.
-Elemental uses the spirits of lightning and fire to deal high damage from a range, this specialization can duplicate their spells and cast while running making them extremely potent in combat.
Shamans are fun to play and have very interesting and fluid mechanics.
Warlocks are a pure DPS class who lack mobility in combat but make up for it in being able to share damage taken with their minions, making them almost tank like.
-Affliction corrupts an enemy and afflicts them with deadly fel magic to slowly destroy and leech their life energies.
-Demonology empowers the Warlock's minion and allows them to occasionally metamorph into a demon, increasing their spells damage twofold.
-Destruction uses fel magics to destroy an enemy in fel flame, commanding chaos energies to pierce any armors, physical or magical, an enemy may have.
Warlocks are durable, extremely deadly and fun to play and have amazing crowd control abilities.
Warriors can tank or DPS and use next to no magical abilities to complete their roles.
-Protection specializes in controlling enemies through AoE stuns, charges and bleeds.
-Fury can dual wield 2 handed weapons and can deal devestating burst damage.
-Arms can helicopter with their weapons.
Warriors are a great class with fun mechanics such as charge and heroic leap.
If you are looking for a guide to play any of the classes, click the icon below!
