As a healer, these are things I love:
(Priest - Holy)
-Chakra. I didn't think I'd like this, but I do! I spend time keeping the Sanctuary version up and running. It adds flavor to everything I do. I was actually saddened when they took some of the versions out.
-Guardian Spirit. Ohhhhh I can NOT tell you how many times this has saved people I otherwise couldn't have kept up with. I love you for this. Really LOVE it.
-All the new ways I have to heal. I can rotate around, swap out tactics, alternate dots and direct heals. I have stuff to really DO.
-Spirit of Redemption. Honestly, I'm not good at PVP. And rogues, dk's, etc, LOVE to destroy me first on the battlefield. I'm soft and squishy and don't take all that long to kill, and frankly, I'm a danger to them in being support for those who DO hurt them. So.... yeah. Spirit of Redemption is the form I spend the most time in. *laugh* I'm immune to damage and have 6-12 seconds to HEAL everyone I can get a heal on. I'm so grateful for this - I'd probably be pretty useless in battle without it. :)
-Light Well. I've heard people say the thing is useless. But it isn't! No, I don't use it in every raid _now_, but that extra dot heal is very useful. It stacks. It helps. It's more healing for less mana than almost anything else I can do. Seriously, if people actually click on it, it can make a HUGE difference in how things go - 10 charges of renew for one little bit of mana is a beautiful thing.
-Holy Nova scaling. <3 . Just <3
(Priest - Discipline)
-Penance. hahahaha this spell is absolutely hilarious - my husband once called it "Teabagging them with your Golden Healing Balls".
-Being made into a tank for ten seconds by a discipline priest is funny as anything - even a squishy can be hard, for a little while!
-The fact that they're GOOD at it. Discipline priests are actually better single-target healers than Holy, if played properly. It's a really viable spec now. <3
-Smite-healing. That's just fun.
(Druid :) )
I don't play this enough to really know it well. But omg - I see druids TOP the healing charts in every bg I go into. They outheal priests. I'm jealous! :D I don't know what they're doing to be healing MORE than the priests, but dang! It's impressive, and I'm considering rolling a druid just for that. (Well, that and the flexibility - druids can do EVERYTHING :) ).
So come on, folks - show Blizz what you love about the game they spend their lives making for us. :)