This was my costume for Blizcon '09 and for Halloween. That year they were only a couple of weeks apart.
I had LED lights in the shoulders to make them glow and the crown was crafted from cardstock so it was light enough to be suspended above my head on one of the silly spring head bands.
For those of you that play wow... I had a fabric bubble on my back that was made from one of the sun shades for your car windows... this way I could fold it up and then pop it out as if I set off the pally bubble. Also I had green feather boas I made in to harthstones. I'm a dork and proud of it.