Waters:
Primarily mages/support.
Fires:
Mainly warriors, mages are good as well. Built for powerful attacks, no known hidden skills though.
Earth:
I'd have to say warriors, but the hidden skills for a mage are powerful as well.
Wind:
Yeah... wind doesn't seem great to me either. Tend to have low CON because they need points in other things (especially AGI), and their weakness is fire (built for powerful attacks). The wind goddess skill, Vanish, is very useful though... unless against a fire mage.

My top choices are Fire and Water, Earth can hold its ground, but Wind... just not my choice.