Definitely the story and character development. The stories are consistently good (except for FF8, which I found somewhat lacking - and I haven't played FFX). Definitely NOT the gameplay. FF1-FF3j were all about gameplay, since the battle system was a new thing in video games (RPG's in particular). However, they never really changed or improved the system (it's still just "wait until my meter fills up, then attack the enemy" - there haven't been any real significant changes, except maybe limit breaks). If FF was known for its gameplay, they would have come up with something new long ago. But I'm perfectly happy with a great plot and repetititive game play.