Well, you can't really say that FF7 was the most important because it was so popular.

Importance is defined in a few other ways, too.

However, if you think that Final Fantasy games weren't popular before 7, think again. I was in line to buy FF6 the day it came out, and after a few hours in line, I went home empty handed because they had sold out.

Sure, 7 was the first US FF game to have major TV spots, but FF6 (or "Final Fantasy III" as we called it then) was wildly popular. FF1 was successful, FF2/4j was even more succesful, but FF3/6j was really anticipated in the gaming community.

However, I will accept that 7 was incredibly popular, even outside the gaming community.

You'd see advertisements for FF3 in gamepro and EGM. You'd see advertisements for FF7 in non-gaming magazines.

So I guess FF7 is the most important. It was the one that put Final Fantasy on the world spectrum. But it was not the one that made a name for the series in the gaming community.

To US VGers, it's probably FF1, 2/4j, or 3/6j. But to the rest of the non-gaming world, almost certainly 7.