I think I would go with the .hack series,
YES, I know the 7 games were ALL critically bashed and didnt sell out the A$$, but the games, IMO, were phenominal, more specifcally the ones following the haseo story arch.
They were immersive worlds, the stories were brilliant, the combat was simple but enjoyable, it felt like an MMO, you truly felt like you were the player who was playing the game with touches like emails, forums, etc, I could go on.
Maybe im wierd lol