BEST FINAL FANTASY STORYLINE *possible spoilers*
I'd have to say Final Fantasy X-2. The side story with the Crimson Squad was pretty good, especially the scene at the Bevelle underground and the whole Den of Woe thing. I really liked the character of Shuyin cuz he's a total badass from start to finish and probably one of the most enjoyable villains ever since we see his two sides. And then you have Yuna who is always talking to 'him'. I liked how Square made 'him' feel like 'me'. Whenever she talked to the player she always referred to 'him' and when she's in the farplane and the player presses 'x' to whistle it makes me feel like I'm somehow Tidus' spirit or suttin.
Some people will say VII but nah. I liked VII cuz it was fun to play. The storyline was good but it deteriorated towards the end. And at times I felt that Cloud was in love with Sephy more than the two females fightin over him.
VIII's story was all over the place and found myself wondering who the damn villain of the game was, was it Seifer? No. Was it Edea? No. It ended being Ultimecia who recieved 5 minutes worth of character development.
X-2 takes the crown, HOLLA FRONT!