I used Zidane,Garnet,Vivi,Freya in my first playthrough, but my standard team is Zidane,Garnet,Vivi,Steiner in my main playthrough. I really like Zidane as a character/fighter, Vivi too. I pick stupid Garnet only because of her Summons, mainly Bahamut who in IX looks fantastic. Else i'd pick Eiko because she is a better white mage and white magic is more important (although i had boosted Mega Flare's damage to max and it rocked, esp in trance). Steiner is there mainly for his synergy with Vivi and his own awesome skills.
"Divine Etro. Go peacefully to your rest. I will stand guard over your legacy."