I'll have to admit that X-2s battle system (not the class and class-changing system mid-battle) is one of the best I've played. It was fast pace and commands overlapped with each other to form combos, it actually made you sit there for a second saying "Not gonna use Darkness yet, gotta let the Thf begin to attack then I'll combo Darkness off it"

As for IX, imo, its the best PS1 FF. VII was amazing, and it set alot of standards, but oldschool Final Fantasy combined with the new technology that PS1 offered, made for an amazing game