Stats87 on 07 July 2008
Best: Xenogears and FFX,
Worst: Legaia 2:Duel Saga (excellent battle system though)
Kingdom Hearts, pretty much any Suikoden and Final Fantasy VIII are all excellent as well.
There hasn't been a Final Fantasy story that I didn't like. Xenosaga was stellar, Star Ocean:Second Story was pretty good, SO3 was decent and I liked both Valkyrie Profile's.
