The birthplace of the console RPG.
The template by which all other console RPG's have come from. This game was carefully crafted to take a complicated genre of RPG games and make it easy for the masses to grasp and understand and enjoy. It successfully accomplished these goals and became a cultural phenomenon in Japan as a result spawning a huge series of games and spinoffs as well as an entire genre.
While it hasn't aged well you can see how many of the things we take for granted today began here. It's still a relatively enjoyable game if you go in knowing what you're getting into. Myself I played this when it was first released at the tender age of 7 and was blown away as I had never played anything like it. The game is structured to challenge you and requires some grinding. However it's not completely unforgiving and can be beaten with a little luck even without maxing out your character.
A fantastic beginning for one of the most popular genres out there!