My main team is Vaan, Balthier and Fran.

Vaan - DD - Light Armour - 1: Knives with Shield; 2: Ninja Swords
Balthier - Tank - Heavy Armour - 1: Poles; 2: Guns
Fran - All Around Mage - Mystic Armour - 1: Bows; 2: Katana

Poles are fricken awesome because too many enemies have low Magic Resist, making it very easy to do a lot of damage to them, especially when it multi-hits. On the other hand, it seems that "Reflect" will cause them to do no damage/miss (can't quite remember).

While statistically speaking Penelo is the best mage, I just love Fran.