Final Fantasy question: where to begin?

I was chatting with a friend about my Final Fantasy X replay (about which more at another time), and she expressed an interest in the series but was wondering where to start -- which makes sense, it's a huge series with no clear starting point since so many of the games stand alone. I have my own thoughts on this subject, of course, but I wonder what the rest of you think.

So here's the question: if you were to rec one and only one Final Fantasy game to someone who has never played anything in the series, which game would it be and why?

( My answer behind the cut, so as not to prejudice your comments. )

Update, Tuesday evening: it turns out that my friend doesn't have access to most of the platforms that have FF games made for them, so this discussion is mostly theoretical, alas. But thanks, still, for weighing in, and feel free to keep commenting! It's still an interesting topic and I've enjoyed seeing what everyone has to say.