Best FF? Well, the ones I've played:
FFI, FFII, FFIV, FFV, FFVII, FFVIII, FFIX, FFX, FFX-2.
And after playing all of those, the best one is purely the first PAL, FFVII. Reasons?
Firstly, Cloud Strife. What differance does he make? A lot to me. he's not your average hero. At the start, he's only with the good characters as they're paying him. Says a lot really when the hero needs to be paid to be a hero. Then, as the game continues, he gradually becomes more and more wound up in it. BUT he never becomes the whole 'I'm going to save the planet!' hero. He says it himself, he's not in it to save the planet. he's there to settle the score with Sephiroth for destroying Nibelheim[spoil](Plus I think he wants to protect Tifa

Nibelshipper, right here,)[/spoil]. He says, from what I can remember, that he knows none of the heroes are there to save the planet, they're all in it for one reason, and they should know what that reason is. Cloud is just an average guy who's, by a bizarre twist of fate, has been made the one person who can save the world. he isn't destined to save or destroy it, he wasn't made to do either. He was just a boy, with a dream, who's life just kept getting worse.
Secondly, there are THREE Bahamuts. No other FF had more than one, and this has three. Bahamut, Neo Bahamut and BahamutZERO.
Thirdly, the characters in general. You've got:
1) A guy who's been dragged into saving the planet as he wants to get even witha psycho with a big sword.[spoil]And protect the one person he has left[/spoil]
2) A girl who's only reason left in life is to be with the person she loves.
3) A man who's lost everything except his daughter and is willing to do anything to protect her.
4) A creature who represents the last of his kind, and wants to protect his home like his father before him
5) A man who had everything taken from him, and is now seeking redemption for the sins of doing nothing to stop it.
6) A girl who is willing to do anything to keep the old ways of her home alive.
7) A spy turned good from meeting a group of people he couldn't understand
8) A man who has never given up on his dream despite having every possible problem thrown in his way
9) A girl who has great plans and untapped power, who is willing to give everything, including her future, for the future of everyone else.
If you can't love those characters you defy my logic. And if you can't guess who is who:
1) Cloud
2) Tifa
3) Barret
4) Nanaki(RedXIII)
5) Vincent
6) Yuffie
7) Cait Sith
8) Cid
9) Aeris
Next, the games plot. Most original thing ever IMO. The Weapons, Meteor, the Cetra, Sephiroth, they're all characters and story twists you'll never forget.
Also, Cloud's speeches. They rule. ESPECIALLY the ones after Mideel. The 'illusion' speech, the 'why are you here speech' and the 'why did you stay Tifa?' speech. Every single one leaves an impression on you.
Finally, it's graphics and character designs. Not much today, but the character designs are sheer amazing, and the graphics back when it was released were years ahead of it's time.
Overall this game was amazing. I have yet to complete it, and since it was the last of the big PS1 three(FFVII, FFVIII and FFIX) I played, at first I was sceptical. The moment I made it past Disc 1 though, my eyes were opened. The game is the best ever. FFIX is a close second, but FFVII will always be the best.