As much as I personally dislike Eiko, I think she's a decent white mage. Probably the same as shion - Garnet for summons.
Garnet cause she gets Bahamut and Leviathan and all the cool Eidolons!
Eiko - Cause she's the better White Mage and her Eidolons are more pracitcal though not as flashy
Meh, I always just used Quina as my healer. White Wind and Full Powered Frog Drop PWN
As much as I personally dislike Eiko, I think she's a decent white mage. Probably the same as shion - Garnet for summons.