Thinking about it, three clerics would be neat. Have them related in faiths somehow. Take different views of the same subject.
Magic
Evil and misuse / force of it
Good over abundant and helpful
Neatral balance and keeping magic from harming nature's way.
Or do that with Druids
Or do a Mage, a Cleric and a Psion and they can discuss the differences of their powers at family reunions.....