PLD THM WHM BRD SCH = Put all points into Attack Stance

ARC SMN = Put all points into Defense Stance

MRD WAR GLD LNC DRG PUG MNK ARH CNJ BLM = Put all points into Healing stance

Just an example of what I feel optimal companions should be, towards your main class/Job, and don't forget about utilizing cross-skills of other classes.