IX, which remains probably my favourite.
VIII, which I love to death, and the characters... well, see my chosen avatar.
VII, played it last (not counting VI, which I hated, V, which I got very bored of, and IV, which I marely started before giving up on).
I remember thinking that I could see exactly why people would love FFVII, and I did enjoy it a lot, liked the story, liked the character, liked most of the pacing, the action, the cutscenes; all that yadda. It wasn't my favourite, and it wasn't my first, but interestingly, if I had been told to choose one to remake, or add sequels to, back then (before they actually got made), I would still have said VII was the best of the bunch.
IX and VIII were utterly self contained, and VIII's ending was still just a little too 'wuh?' for me to really stomach, but VII had (and still has) the best and most expandable story of them all. So much was open to interpretation, so much was done right, that I think the real reason people dislike it (to turn your question around) is simply down to hype backlash, because nothing can ever live up to the hype.
Undoubtedly, the game is not as good as advertised, but that doesn't make it bad, it just makes it shallower than you expect, which tends to leave people feeling like they've been ripped off, hence, apparently, hatred. Hype leads to expectations, expectations lead to disappointment, disappointment, leads to Hate...
Wait just one good gorram minute, why do people hate this game so much? (Please don't answer this, I include it for purposes of amusement only.)