Back when Innervate was spirit-based, you had basically 2 choices. You could give your innervate to a holy priest and let them go nutty with circle of healing (pre-nerf), or you could give it to an arcane mage and let them rack up the deeps. Now that innervate is based on the casting druid's base mana pool, any mana user (probably a healer) will benefit from it.
We got our first boss down in ICC10 last night, and I found myself getting all the innervates (from a resto and feral tank druid). Now, the funny thing is, I actually think my mana regen is pretty great right now compared to a while back. I got a usable mana regen trinket, and the new 3.3 gear has been mostly itemized for haste/mp5, so I've been able to pick up mp5 along with my delicious delicious haste.
Compared to the other healers, though, shaman have the fewest mana regen tricks. Other than mana tide totem (which affects all healers really), we live and die by our own mp5 and the mana we get back from critting a Improved Water Shield bubble. Pallies have Divine Plea/Divine Illumination, Priests have Shadowfiend/Hymn of Hope/Inner Focus, Druids just don't seem to have that bad mana usage, and our resto druid is glyphed so that her innervate gives her mana back too. Right now our mage is trying out a frost spec to see how the 3.3 changes affected him, so that's not really a valid option either.
So this shaman is sitting on mountains of mana, chain healing his ass off. Woo!