My group has definite plans for two things: Pokemon, and Adventure Time. So I know I'm going as Moltres (gotta get working on it, oh dear. Been too focused on helping our Zapdos. >.<) and as Flame Princess.
I'm still trying to figure out what else to bring. I've finally got a costume library kind of built up, so it's between Finland from Hetalia, Genma from Naruto, or Felix from Golden Sun...