Final Fantasy VII (Playstation, 1997)

For the first time in series history, a Final Fantasy game was released on a non-Nintendo console.  Square was planning to release Final Fantasy VII on the Nintendo 64, but when they found out that the system would still be using cartridge-based hardware, they reconsidered.  The two-year-old Sony Playstation looked like a far better option, since it used CD's for its games, which offered more storage space to make a bigger game.  Even with that additional room, the game spanned three discs.  Well worth it though, since Final Fantasy VII was the most massive and ambitious Final Fantasy game at the time, and my personal favorite.
The story centers on Cloud, a pessimistic and anti-social ex-member of SOLDIER, a military force of the totalitarianist government, Shinra.  He joins a terrorist group called AVALANCHE, led by Barret, who blow up energy reactors in the city of Midgar.  These generators, called mako reactors, are using the planet's blood (or lifestream) for electricity.  Cloud doesn't care about their eco-extremist views, he is only interested in payment for his services.  After a successful bombing of one of these reactors, AVALANCHE regroups at the bar run by Cloud's childhood friend, Tifa.  She provides some of Cloud's motivation, since he made a promise to her (when they were children) that if she needed a hero, he would be hers.
Attempting another bombing, AVALANCHE is caught by Shinra, and attacked.  The attack separates Cloud from the rest of the group, and he encounters the flower girl, Aeris (Aerith in Japan).  Not long after meeting her, he has to protect her from police who wish to abduct her.  Cloud finds out that this is because she is the last living descendant of the Ancients, a race of magical beings who came to Earth seeking refuge, but were met with discrimination and then, extinction.  Cloud comes to fall in love with her over the course of the game, before one of the most famous moments of this game.  Cloud and Aeris manage to regroup with AVALANCHE, but not before Shinra attacks their hometown and base, killing every member but Barret and Tifa.  They decide to retaliate by attacking Shinra headquarters.
This attack is a failure, and they are captured and put into holding cells to be later executed.  Before the execution, however, some mysterious force has destroyed large portions of Shinra HQ, allowing Cloud and friends to escape.  The assailant is revealed to be Sephiroth, former leader of SOLDIER, and long thought to be dead.  He came there to liberate Jenova, a malignant genetic experiment, and his mother.  Sephiroth wishes to summon a meteor to blow a hole in the Earth large enough for him to merge with the lifestream, allowing him to become a god.
Such a lengthy explanation of the plot is necessary to explain the game's revolutionary play mechanics.  The new system for customizing characters is Materia, magical spheres that can be equipped to any character's armor or weapon to grant them its ability.  Materia exist for all skills, from magic spells to summons to statistics boosts.  As you battle, you gain experience points, which are attributed to characters and Materia.  They may level up, multiply, and be conjoined with other Materia.  Similar to Magicite from Final Fantasy VI, Materia allows any character to learn and master any skill.  They also play into the story.  Materia come from the lifestream of the planet, and it a Black Materia that Sephiroth plans to use to summon meteor.  The only thing that can possibly stop meteor is the White Materia, which only Aeris can use.
Battles have also been re-imagined.  For the first time, your party can only be comprised of three characters.  Another first is full-3D modelling for battles (normal environments use pre-rendered backgrounds, similar to matte paintings in old movies), and limit breaks.  Each character has a Limit meter that fills as they take damage, and when it is full, they may use a variety of character specific attacks and skills.  Most of Cloud's limit breaks involve dealing heavy amounts of damage to enemies.  Most of Aeris's are defensive moves, such as healing HP for all characters.  Limits would become a mainstay in the series, though it would be re-named in a few instances.
Final Fantasy VII has received much praise over the years, which has recently turned into backlash.  Many die-hard fans consider it to not only be the best game in the series, but in all of video gaming.  I think that like movies, determining which title is the "best" is impossible because of how vague a statement that is, and how difficult it is to compare games of different genres and generations.  I don't think Final Fantasy VII can be called THE best game of all time, but it is one of the most important.  It was the first RPG to be both a critical and commercial success in the United States which would turn the genre and Square Soft into industry giants to this day.  Its themes of environmentalism, terrorism, fascism, poverty, and even religion are handled fairly well given the atmosphere of the time it came out (we still have trouble talking about these things today).  In spite of all of the worshipers and detractors of this game, it can be considered one of the best video games ever created, and a fitting end to the golden age of Square Soft.