My 2 cents....

To me, I love both FF6 and FF7 equally. Both had really good storylines, and both had some real nice sidequests and battle system. FF6 has a bit of an edge with better music and more characters, and of course, the most coolsome villain in all of FF, Kefka!!

FF4 was good, with a nice story and nice characters, but hampered by the "old-skool" RPG thinking - too many random battles.

FF5 was excellent!! Loved the job system, it's probably the best system in FF and has been refined in FF Tactics. Also had some very memorable characters, of course the star was Gilgamesh with his awesome music and the very memorable "Excalipur" incident And he kept his promise of "returning" when he returned to FF8

FF8 was ok, but hampered by the battle system. The Draw system was sooo tiring, needing you to draw spells, and you only have limited uses.....

FF9 was great. A very memorable story, with FF going back to its "roots" or so to say, with each character having the standard jobs already assigned to them.

FF10.....was ok in parts, but overall kinda lacking the epic feel of other FFs....FFX-2 I won't even mention, since I played 5 minutes of it and dropped it like a bad habit...