Izumi Konata is the hardcore otaku protagonist of the Lucky Star series. She has a tendency to refer to several popular games, anime, and manga; including Yu-Gi-Oh! and The Melancholy of Suzumiya Haruhi. She has many figures of Suzumiya Haruhi in her room and even cosplayed her in the Cosplay Cafe she works in.
Did I mention that both characters have the same seiyuu (voice actress) too? Awesome cosplay by Aka-san! Thanks to Raichuu for sending this in!