ffVII is my greatest gaming experience to date... however: you REALLY should know that it became so popular because it was only 75% complete ^^ there's a great FAQ on gamefaqs on that, and when I read it I realised that was the reason why I liked the game so much
I suggest you ppl read it too
the thing is with OTHER final fantasies to me, is that they bring you a story which they finish. there haven't been that much final fantasy-games that had open endings (haven't finished X yet though, still working on that, so can't judge for that game), there always was a finished story.
SPOILERS:
On top of that: the story was full of plotholes (like: the scene at the end of disc 1, that wasn't Sephiroth but Jenova. but why would jenova do such a thing? or the flashback with Cloud and Zack, where in time can that possibly have happened? BEFORE or AFTER the Sephiroth flashback at Nibelheim (really, think about it, Zack could only become a SOLDIER when implemented with Mako, however he escaped with Cloud after they had been mako implemented, but where in time does that place the whole Nibelheim flashback? the only possibility I could imagine was that Zack was implemented twice, but that's kind of rubbish), how did Cloud survive the whole Sephiroth stab thingy, ...
and that's the stuff I like: the game leaves certain things to the player: you should figure some things out yourself. And that's how you can enjoy that game over and over and still discover new stuff
the other final fantasies are way to simple at that subject, EVERYTHING is explained, there's no more room for an own though. that's also why I always like the first half of the storyline in a ff game the best
(gameplay is better in the last half though
)