Out of the games I played it would have to be Final Fantasy IX. Gaining the Hilda Garde was such an astounding experience that started with the secret of Eiko's pet moogle, Mog, the defeat of Zorn and Thorn at Mt. Gulug, the discovery of Cid's long lost wife, Kuja's ambitions, finally having Cid transform back into his human form, and Hilda revealing the plan's of Kuja. Story wise it revealed a lot as so did X's with the reveal of the summoner's death at the end of their journey.