In your opinion, which Final Fantasy is the best?

I've only played Final Fantasies 1 (very little), 2 (very little), Tactics Advanced (finished a couple times), and one of the Kingdom Hearts (I think I finished, but I don't remember). I want to get back into them, so which do you think is the best. For the record, I really liked Tactics Advanced, even though I am aware that it's sort of the kiddie version of Final Fantasy :P