You're likely already aware that one of the great new features to be unveiled in the Wrath of the Lich King expansion is the ability to change your character's hairstyle. A number of players (including myself) have actually stopped playing certain characters just because our original appearance choices didn't turn out as good in play as they seemed in the character creation screen. Some (including myself) have spent a long time thinking about what a new character should look like and trying out many variations, playing for a bit, deleting them and trying again until you get something you know you can live with for the rest of your character's life.
Soon, however, our characers' hairspray will no longer be stone-stiff, and a new era of creative exploration will open up to Azerothians. Existing characters with ugly hair may get a second chance at coolness -- but as many already satisfied players know, your characters' good looks often come from a desire to make them fit, as closely as possible, some image we already have in our mind.
So tell us of your dream for your character, how you envision him or her when you close your eyes. Do you want your Death Knight to look like Darth Vader, or -- heaven forbid -- Chuck Norris? If you like, you could link to a picture you like, or even draw your creative vision for us!
My own most vivid character visualization was for a night elf rogue I had in mind. I wanted her to have the look of an angel who used to live among the stars in the sky, but had somehow gotten lost on earth and forgotten her way home. In hindsight, I was probably very inspired by my favorite Neil Gaiman novel, Stardust, in which a star actually does fall to the earth... and breaks her leg.