Final Fantasy VI, of the ones I've played it's definitely the only one I love, specially the GBA version, since it goes with me anywhere it gives me more incentive to finish it since I tend to not finish RPGs, though I still haven't finished it, it's definitely the one that's held my interest the longest, though considering how much I love Tactics Ogre I really should play FF Tactics, wouldn't be surprised if that becomes my new favourite, and though I liked Tactics Advance the law system was greatly annoying to me, not to mention I found it more grindy than Tactics Ogre.
But seriously FF VI is damn good, and everyone that says they all suck clearly hasn't played it, I mean even if you don't like it I'm pretty sure nobody would say that it's a terrible game, the atmosphere is great, the characters are likeable and interesting and for the most part well developed, the music is just undeniably fantastic, even though it's a 16-bit game it still looks pretty damn good and has a lot of personality, I mean there's nothing about it that you could say it's terrible, you can say you don't like it but it's most definitely not a bad game.