Damn you, Squeenix, for making me buy this YET AGAIN for another damn system. I'd have been able to pass if it were just another re-release, as I've played the excellent FFIV GBA version, but this remake looks gorgeous.
IV and VI are neck and neck in my book. Both have amazing character designs and great gameplay, not to mention some of the best music in any game, ever. VI definitely has a fantastic ensemble cast and a story that's massively epic in scope; IV's story is tighter and more coherent, as well as characters that are a bit more differentiated ability-wise (having everyone be able to learn magic at the same rate in VI is a mixed blessing, gameplay-wise).
I just wish they'd get around to a DS (or even GBA) release of Seiken Densetsu 3. It'd be a damn sight better than anything they've released under the Mana banner since Sword of Mana.