Played FFXI (the MMO) for a while. Was a terrible, hardcore grindfest for a long time in the Japanese style. However, they made several changes over the years to make it solo or low-man friendly. IMO its a very good MMO now. It's achieved a pretty good balance of providing a challenge without being too difficult, or too easy and kiddy-friendly like WoW supposedly is (have not played). Graphics wise it is, of course, outdated. It is available for 360 tho, which is nice, and about any computer can run it without being taxing. If you've played FFXII, the battle system is similar to that, but much better cause you actually control (and can micromanage if you choose) your character.
In typical FF style, the storyline in FFXI is outstanding and is probably as good as it gets for an MMO, especially the Chains of Promathia expansion. Wings of the Goddess has some good stories as well. Not so much in the main storyline, which is ok, but in the nation missions.
FFXIV, on the other hand, is absolute trash from all accounts I've heard. But they are totally revamping the game (2.0), so it may be worth trying. Graphically it is top notch for an MMO, but can be taxing without a higher end PC.
XIII-2 is really good. Gameplay wise, more fun than XIII. A lot more freedom. Debatable on whether the story is better or not. It involves time travel, so that should tell you something. Has the most powerful villain in FF, maybe in all video games, without spoiling too much.