Briefly reading through here, and just playing around a bit on wowhead, I've seen a few styles of healing builds, not trying to have them rated or anything, but I've seen full resto, resto with a subspec, and dreamstate builds. These may not be cookie cutter builds or anything, but something along those lines.
What I'm wondering is if the following assumptions I am making are correct (and if I'm wrong, why I'm incorrect, and to what degree am I incorrect).
Full Resto: This build is useful for healing when you know that's all you'll be doing. It allows you to use healing touch if you need a quick heal between cooldowns of swiftmend, but does not allow you much utility in feral or caster forms. Useful for healing, but not DPSing, off- or main-tanking, or PvP.
Resto With a Subspec: This build would allow small off-tanking ability, or some added PvP utility if subbed in feral, and would allow some extra buffs/debuffs for PvE or PvP support if subbed in balance. Would not have the extra bonuses to HT, but with how good your HoTs are you shouldn't need it a whole lot, and natures swiftness makes up for several talent points. This would take the full resto build and drop a few talents that would be situationally usefull, and pick up other talents that would be situationally useful - only instead of just healing picks up added utility.
Dreamstate: This build would allow for healing touch to become incredibly mana efficient, and allow for you to rarely go OOM. Would allow for a lot more soloing power (caster in plate) while letting you DPS should your group not need a healer at the time. Popping out of moonkin form you could still be a formidable healer, albeit not the master of HoTs that the other builds allow.
Summed up: full resto offers great healing power in either playstyle (HoTs or HT spam) but no utility, resto with a subspec will allow for extra utility/support in PvP and PvE but not use HT as effectively, and dreamstate will allow for good (but not great) healing and DPSing in PvE.