As Skyrender said: FF1 started it all and saved them from bankruptcy. Without FF1, there would be no Square that has merged with Enix. FF1 is the most important entry for that alone.

i can't believe the thread started doesn't even mention the fact that FF1 was literally the last hope for square. It was called final fantasy because it was likely to be square's final game unless it took off. None of the other games matter without FF1.

im rally going to have to go with 1. not only did it save square but it set up the system of similar feeling games with lots of things in all of them, but forced every new game to have a completely new world.

i think ff's identity really came from the fact that each game had both a solid base and extreme amounts of creative freedom to go forward, both of which where kind of forced upon them by ff1.

 I intentionally left that out because I figured that most people would have known that one already (particularly because this is a game forum), and like I said in the OP, the question is open ended, so I didn't want to restrict people to just "if it wasn't for game 1, nothing afterward would exist" because then the most important game for every franchise is the first. Each game series could be boiled down to that (big example would be Super Mario Bros, argueably the game that saved an entire industry, but it's importance to the series has diminished some what since it went into 3D), and there is a reason why every FF deserves a mention, so while we could say that FF 1 is the most important because without it square and FF wouldn't exist, let's keep it interesting, because alot of the things in FF1 have been lost with the recent installments (particularly "orbs" being the original "crystals").

Of course everyone is entitled to their opinion, and I'm not going to claim that your view of FF1 being the most important is wrong (don't think anyone should make comments like that about anyones posts), I just figure we should judge both the additions the game had to the series and it's impact on history (and not just one or the other), because FF1 lacks in the former (aside from laying down the foundations of course). 

@Khuutra: the phrase "putting it on the map" implies that it made it cool or well known, because up until FF7 Final Fantasy had a mostly cult following (arguable of course, but that seems to be the general consensus). 

For me ,its FFVII.It put the series on the map worlwide.


And keep an eye for FFXIII ,that should be EPIC.

Obviously 1, but the second most important is FFVII even if it is highly overrated it still made the FF series even more popular than it was.

 I think you're misinterpreting what people mean by saying 7 put the series"on the map."  In fact you nailed the essence of it with the acknowledgement that FF7 made it "cool."  7 made the genre more mainstream than it ever had been.  I would probably never played an RPG if I hadn't played FF7 

"Not just talking about which FF game put the FF series on the map"  From op

Um sorry, but did you read the op? That is incorrect anyway, because the final fantasy series was always on the map, 7 just made it more popular than it already was. 

FFVII possibly defined the "console war" for that generation and obviously that makes it highly important. FFI on the other hand saved the company and created the series. I think the answer lies in either of those two games, with neither necessarily the best in the series, however none of the other games come close in terms of importance.

For me it's 7 without a doubt. The massive marketing budget Sony put behind it made FF games what they are today and shaped most of the games afterwords.

There is only one that comes close... FF1... as not only was it the one that started it all, it saved SE from bankrupcy.

I guess you could claim the masterpiece that was 6 is what convinced Sony to buy and push FF7 but I think it was 3-6 that made sony do it not just 6.

Sure FF games were already really popular RPGs... but they weren't "Sell on name brand alone to millions" good.