I don't know how this wasn't mentioned right off the bat but look up .hack//Sign if you haven't seen it already. It takes place inside an MMO called The World. Its pretty well done and is a lead in for the .hack/IMOQ )Infection, Mutation, Outbreak, Quarantine) set of games but despite that it is a stand alone piece of work. It can be very slow paced because much of it is dialogue instead of action but its still really good. It can get pretty heavy at times in themes like escpasipism, anxiety and relationships between people and how they affect others. If you like that than I would follow it up with .hack//Roots which is the lead in for the next set of games, .hack//G.U series, but I would have to say .hack//Signs was better than Roots but it has been a long time since I watched either. Also you have .hack//Legend of the Twilight but that mainly is a sequal of sorts to the first set of .hack games and might be better off watched after you played the games or read a synopis on them. I'm not sure because its been a long time since I watched it.