On this playthrough I have it like this so far:


Vaan - Swords.
Ashe - Swords.
Basch - Axes, hammers or swords.
Fran - Bows.
Balthier - Guns.
Penelo - Daggers or Staffs/Rods.

I don't remember what it was during my last playthrough, though. Generally I just like to keep Fran and Balthier equipped with bows and guns, respectively, and the rest are a bit of experimenting/whatever I feel like. This time around, though, I'm making Penelo more of a mage than the others, so staffs and rods are probably going to be the weapons I'll give her from now on. Oh, and I like giving Basch hard-hitting weapons, like e.g. Axes.