My alternate Druid healer runs Heroic Utgarde Pinnacle and using a cute little mouse-over Thorns macro, and the Thorns glyph that reduces the cool down, to put it on the tank. I only used Thorns at the beginning of pulls. Overall damage done by the tank at the end showed 14% by thorns, which was ranked number one.
Druid healing post 4.0.1 at level 80 is over powered. During the Bone Storm I went to tree form, put instant cast regrowths on anyone taking damage, carpet bombed lifeblooms on the whole raid. During the raid I never casted a nourish, and I only used Healing Touch when Nature's Swiftness was up. I swiftmended on the tanks constantly, whether they needed it or not, just so I could see the pretty green circles.