IX. In terms of the characters, I felt it was relatively balanced unlike VIII, for instance. I feel that the characters were all developed to at least a moderate extent throughout the story even if some were sadly neglected in the latter half of the game (e.g. Freya). The music is utterly divine, I love the use of harpsichords, organs and the like which isn't seen too often in computer games. The world was vibrant, interesting and fun to explore. While the card game was a let down, the chocobo mini-game and sidequest was the best in any Final Fantasy game. The story was interesting and flowed pretty fluently; it wasn't stop-start. Kuja is the only villain from the Sony era that I rate that highly.

In short, IX is brilliant.