My Favs ones:
1).-FF VI :So many characters plots,all of them with so remarkable and full of deep feeling sensations,crossing between them and forming an epic,unforgetable quest,not only for save the world,for find and accept themselves as well.
2.-FF VII: An alien main villain,a rulership company overexploting planet's main resources and many greats individual's story.
3.-FF VIII: A great, unforgetable as well,love story,revolving between a more mature terms mixed with a compelling school (garden) life.Laguna rocks too.
4.-FF X: Painful story,impossible to not feel the sadness and despair around the whole game,fight against the established religion and ultimately against the same sacred source of your belives?Greatness.
5.-FF IV:The first "complex" FF's story,redemption,selfsacrifices till the end (Kain,you rocks) and a great cast of characters (Tellah!!)