I'm generally not a fan of Halloween costumes that are variations on the "sexy X" theme, with X being anything from a nurse to a superhero (with 98% of them really just variations on short skirts of different colors). Nothing against women in sexy clothing, but in a world in which I can see that every day, I'd rather see something that involves imagination and creativity.
But Emma Roberts
kind of wins, if only because very few people can get away with dressing as their aunt.
(Between this and the lovely proper ending of Scream 4
*, I'm definitely a fan of how Roberts has mined her relationship with her aunt without abusing it; I'm sure she'd love to do a tribute to her father, too, but until someone covers "Mr. Brightside," I'm not sure there'll be opportunities to do so.)*Don't get me started on the eight minutes of focus group bullshit that was clearly added after the fact and which would suck the life out of the movie if I bought it as canon; the movie ends with the line, "Jill, how does it feel to be a hero?" Anything after ruins the experience.