Anyone/anything is up for grabs, vote on your conscience, imagine the wow characters as well and living people or imagine yourself in the gaming environment.
You can choose any NPC, famous character or player who's model/look you like including your own avatars. Just make sure you explain who the person is,, if it's your toon, you can invent a background/desc that can help us see why you like it, smae goes for not very famous NPCs you can state what you imagine they would be like or characteristics you gonna give them that you like or like about them.
Anyone is up for grabs,
EDIT: pics help: especially if the NPC isn't famous or it's your avatar or friends/other player's. Also box art, media pic versions even fan art versions help, but pic and description will help others identify with you.