For me, the choice is Final Fantasy III (I played it on SNES, so it will always be three in my mind).
FF3 had some of the best story telling elements that I had seen and, sadly, that I have seen since. It had a huge cast of characters, both PCs and NPCs, and all of them were given a depth of personality that was amazing considering it was all done with text and animations, rather than the pitiful voice acting that many games have these days.
The story itself was incredible. You didn't have the lone wanderer who was destined to save the world. Instead it was the band of heroes working together to save the world...and failing to do so. Driven by a need for redemption and the hope of a new world from the ashes of the old, they come together again and throw down the evil. The spotlight never focuses on a single character too long. No one is the main character. There are no sidekicks.
The gameplay was simple, given that it was an RPG in the glory days of the SNES. This wasn't a bad thing, though, since the main focus of the game was supposed to be the characters and the storyline.
And finally, the coup de grace, was the opera scene. What RPG has used an opera scene to such great effect since FF3? None, I say.
Final Fantasy III. Best. RPG. Ever.