Now that we have even more healing spells that we actually use, Idol of the Raven Goddess http://thottbot.com/i32387 seems the best idol to me. It provides +44 healing to all healing spells.
Idol of Pure Thoughts http://thottbot.com/i38366 only gives +33 and to Rejuvenation only, seems like a joke.
Idol of Lush Moss http://thottbot.com/i40711 is currently bugged and even when it's fixed still hardly better.