Most likely the deepest story in an FF game. It dealt w/ our journey of life, and what happens when it is over. It dealt with industrialization. It delved into poverty like no game ever had before. People play video games because they have the mean to do this. But this game gave these people insight into the reasons behind poverty. "No one lives in the slums because they want to" is a line I'll always remember.

Yes, characters have died in previous FF's, but they were 2D sprites either being blasted by some weird magical "force" or falling out of something. Sephiroth jumped-down Setzer style on the maiden. And then impaled her. After which Cloud holds her dead body in his grief. Nothing even remotely close had ever been done (or could have been done) in an FF before.

The game expressed characters emotions in a way Square would never have been able to with IV-VI. When Cid loses his dream of making it into outer space, you feel it. When Nanaki howls up to the moon w/ his petrified dad, crying petrified tears, you feel that sh!t. You can't have it on this level in the previous games.

The music was crazy. It was the last time Uematso would use the MIDI type instruments of the previous games, which is where I think his true genius as a composer really lies.

The battle system was great. Having it in 3D, like it or not, made it much more enjoyable. Materia was great. If you wanted a Black Mage, you can make someone a black mage. if you want to give them a random set to essentially make your own class, go for it.

The characters all have in-depth backstories, and segments of the game that develop each character. Most of the Final Fantasies have at least a few characters that don't need to be in the plight to save the world.

And you can't forget mini-games. Possibly the best selection in a Final Fantasy (Motorcycle, snowboarding, submarine), and one of the best chocobo breeding systems, where you can actually race them.

All of these elements come together to form "quite possibly the greatest game ever made."