Excluding fighters, i think one of the best parties would be:

x2 Black Mages
x1 White Mage
x1 Thief/Red Mage <- depends on whether Thief classifies as a fighter archetype in your eyes.

Benefits:
- total ownage in the magical department and black mages just look awesome =D
- have a good healer to support your team
- if Thief/Red Mage is placed as leader, it lessens the chance of the other party members getting hit since party leader always has the highest chance of being hit
- mages are awesome

Cons:
- Red Mage isn't as defensively strong as Warriors
- squishy team with low hp
- not useful against magic-resistant enemies

Hope this helps