The best of all the Final Fantasy games, in my opinion. So many of the characters are interesting, they have their own conflicts and problems, and the game does a good job of displaying their emotions to you. The theme isn't really about 'main characters' but rather characters being tied to other characters, like links in a chain that make them stronger. We don't have one character gritting his teeth and saving the world with his giant sword, we have a group of characters who are able to preserver because they are together.
You might want to avoid Suikoden, as it has 108 playable characters.