XIII-2 by a landslide. It further perfected a battle system which I really did like, and gives us a glimmer of hope that maybe, just maybe, we can get dialogue trees in a Final Fantasy game. At the same time, the ending was a bit lackluster and way too open. It's a bit obvious that they're milking that cow for every little bit it's worth.

Also that white mage outfit, so want to cosplay it...