FFXII was my choice, I think FFIX is a close second.
FFXII had a great combat system and a really good cast of characters for the most part. The game has a few minor flaws but was really fun to play over all. It always burned me up that people swear it is too easy as you just set gambits and the game plays itself. I WISH these people would try this past the 1/4th mark in the game and tell me that works. Throughout the game you have to micro manage your characters on top of their gambits to be effective. Gambits purposefully take longer to react to certain situations, requiring you take the helm yourself in order to execute the best strategy. It is also one of the few games in the series that never has elemental magic become irrelevant. In most FF games you use spells for a time, then you can just strong arm the rest of the game. Not so much in XII. It was also the only one for me where I ever felt spells like reflect/blind/immobilize were a constant part of the strategy.
PSN:Forevercloud (looking for Soul Sacrifice Partners!!!)