The multi-media giant known as .hack has produced a lot of different series in its lifespan. Which one do you like best? Here they all are:
.hack//SIGN - The chronological first story, follows Tsukasa as he tries to escape from The World.
.hack (The Games) - Though not technically anime, it has enough story and plot twists to be counted amoung them. This follows SIGN. Here, Kite must save Orca and the other coma victims, while in turn saving both worlds.
.hack//Liminality - the OVA series packaged w/ the games. Mia Minase and companions search the real world for clues as to what is going on in The World (occurs at same time as the games).
.hack//Legend of the Twilight (manga) - The manga story of the adventures of Shugo and Rena, two characters who inheretied the avatars of the legendary ".hackers". They have some wacky adventures and find a stange gil named Zefie...
.hack//Legend of the Twilight (anime) - The anime story of the adventures of Shugo and Rena, two characters who inheretied the avatars of the legendary ".hackers". This story varies incredibly from the manga, as Shugo and Rena run into a strange group of players...
I can't choose! I almost say the manga is my favorite. Though the game may trump that slightly.