I don't really play more than one at a time. I love to focus on one game at a time, probably because I try to master every game I play, like with side-quests, time limits, ultimate weapons etc.

To be honest, any game I play, whether it's FF or not, I always play just the one game at a time. Even if i'm in the middle of a game, and a game I have long awaited has come out, I will buy the game, but then leave it in it's wrapper until I have finished the game I am playing ... but that could just be my OCD rolf :')