Generally, you go with just your two primary stats, with ONE (possibly two) exceptions. The first exception is Thaumaturge/Black Mage needs points in Intelligence (I'm not sure why they didn't make that a primary stat...), possibly go INT/MND on BLM. Another possible exception is Gladiator/Paladin, where you may want to allocate points to vitality... but then again, they really need to do all they can to keep hate, so taking points away from their damage and healing may not really be a good thing.