Final Fantasy VII was the one that did it for me (which I'm sure did for a lot of you aswell), but after that I had to keep buying them right now the only main Final Fantasy games that I don't own is FFIII, FFIV, FFV, FFVI and FFXI. Some day I'll get them all, hopefully they get released on the PSN.

V, it was the one that truly surprised me, not only i can decide what abilities my characters learn, but they change appearance, it was also a nice challenge with strategic value added to it, have the right job and maybe you can make, have the wrong job and you die.

i've played all others but non of them have the impact me like V did.

FFIV. Second Super Nintendo game I owned. It was really, really great.

FF7.

X made me a fan of RPGs. VII followed soon and made me a fan of the franchise.

Final Fantasy VIII made me a fan, but IX and X made me a fanboy.

Final fantasy 4

In fact, I remember after that I went looking for FFVI - when I saw that it had more than a dozen characters, I was worried that it wouldn't be as good, because how could a game with that many characters give enough time to any of them, much less all?

I was delightfully wrong, though.

Final Fantasy VII took my Final Fantasy virginity and made me a fan.

Final Fantasy VIII.

I know I played Final Fantasy VII almost at the same time that the PSX released, but I didn't understand what was happening that much at the time. I played it seriously a couple of years later when they released the new PSX Dualshock bundle, and when I found out that you actually get out of Midgar at one point, I was blown away by the scale of the game (for its time, at least). But then, that's also the part when I felt that the game didn't make much sense and got more and more boring...