That's a pretty great TARDIS dress, but I'm really impressed by the girl in the background -I've never seen a Cassandra costume like this one. These aren't the only amazing Doctor Who costumes out there. In fact, Geek Sugar has a collection of 25 great Doctor Who costumes that are probably from conventions but would make epic Halloween costumes too. While there are tons of David Tennant costumes, and even though he's my favorite, it's actually quite refreshing to see people dressed as Christopher Eccleston or Peter Davidson. Also, I've never seen someone dressed as Donna Noble, which is also great -even if she just looks like a bride when not next to The Doctor.