The Girl with the Dragon Tattoo
I think the title fits the book really well. One of the main characters is a girl with many tattoos including one with a dragon. She is a very odd girl, but extremely smart. Eventually as the story progresses she will be the leading person on the case they are investigating, so it is an appropriate title. It could be called "Thirty years of flowers" because in the opening scene an old man receives the 30th flower from the anonymous person just like all the years before. It could also be called "Blomkvist" because that is one of the other main characters and it is a slightly catchy name.