WHAT? You forgot Gumi. ; w ; I like her the most because her voice seems more original and human like. (Though her voice is actually sung by a young girl. o: ) She's my favorite character aside from Haku Yowane and Luka Megurine.
I love haku, it started out with just a love of her design when I stumbled upon a picture of her on photobucket. That was before I even knew what vocaloid was smile When I finally heard her voice I just fell in love even more, even though her voice is just a pitched version of miku, I prefer it over miku in most cases because its lower and sometimes even more emotional.