Fighter, Monk, White Mage, Red Mage is a good and balanced party, and you'll have 3 attackers and 2 healers in the beginning. Red Mage's Wight Slayer is also very useful against the undead in early spoilerJinn's cave. However, as you progress further in the game, Red Mage becomes less useful all the time. When that happen, you should change him into a Black Mage. I usually change Red Mage to Black Mage around the times when you have to go through dungeons wearing the Mini status since you'll really need attack magic on those parts.