There's 4 kinds of elves in WoW:
Night elves, which are hippies that completely fucked over the world repeatedly(that big ass ocean between the main continents? That's a crater of their making.). They live ontop of a giant tree, get furious at anyone for being on "their" turf, which means any place anywhere that has plants in it. Their most notable member is known for trying to fix an undead infestation by repeating that ocean forming feat. And running away from a demon lord by taking over a fort of said demonlord's underlings and completely forgetting that said demonlord might be there inspecting his minions. Also, url=http://www.youtube.com/watch?v=r9QsSGOcsfg&feature=related]you are not prepared[/url] to face him.
High elves, which are the scapegoat of the night elves clusterfuck and got banished to they made their own state. Got thoroughly trashed by the undead and are way too few of them left to do anything anymore.
Blood elves, which are high elves that went crazy with vengeance after said undead induced near-extiction, are addicted to magic, which they'll do anything for(like pledge loyalty to a bunch of dragons that want to murder every single magic capable person on the planet, demons, the crazy night elf at the top of this post, torturing a being of elemental light(the closest WoW has to Neutral Good deities) or just giving up and turning into a degenerate mutant). They live in a giant opulent city, have magic crystals filled with magic energy which they consume in a manner not unlike opium dens and are exceptionally arrogant.
Nagas/Satyrs, mutants who originated from the night elves almost accidentally blowing up the world. Satyrs are half nigh elves half demons, look exactly as you'd expect and are loyal to the demons. Nagas are seaserpent-men who serve the WoW equivalent of Cthullu. They are also comically evil and all of their zany schemes are ripped from Captain Planet plots.