Alright, I've been bouncing around Holy playstyle for a bit now, and I think I've come up with a setup that's making me happy. This is what I'm currently doing in game. I'm not 100% sure it's what is recommended by Elitist Jerks, et al. Last time I looked at EJ, they seem to have gotten distracted by trying to find the maximum possible rate of Holy Power generation. Which, to me, is sort of missing the forest for the trees.
So this is my current setup.
Current spec and Glyphs: 31/5/5
I take the Word of Glory points, skip Tower of Radiance, and put 1 point in Blessed Life.
On the Word of Glory side, WoG is really good for tank healing. Even if it does less healing than Light of Dawn, it's much easier to keep a tank up with it. I put Beacon on one tank, and mainly focus the other tank.
Healing-wise, my seal is Seal of Insight naturally. My main rotation is 3pt WoG (or LoD if need more raid healing), then Holy Shock, then a HS-DL macro:
/castsequence Holy Light, Holy Light, Divine Light
What I've found is that if I only use HL as a filler, I spend almost no mana, but it seems to need a little more punch. If I try and use DL as a filler, I go dry very fast. The 2:1 ratio of HL:DL seems to drain mana at a nice rate, while doing a solid amount of healing.
Of course, if you need to bust out DL or FoL for intense healing you still can. I've macro'd Guardian of Ancient Kings with DL, so that the emergency heals start together.
/cast Guardian of Ancient Kings
/cast Divine Light
I've also macro'd my trinkets and Divine Protection to Holy Shock, to get maximum use out of them.
/castrandom Divine Favor, Avenging Wrath
/cast Holy Radiance
What this does is trigger one of Divine Favor or Avenging Wrath. It casts whichever one is not on cooldown, or randomly picks one if both are available. I find it's good for spreading out your CDs, while still ensuring that your Holy Radiances are boosted.
Edit: As people have indicated in the comments, this does not work as I intended. The /castrandom can choose the spell on CD, and if that happens then it won't choose a different spell until it casts the original spell.
So that's healing spells. Also don't forget Blessing of Sacrifice and Judge often. I definitely need to improve the amount I judge.
Stats and Gear
Main stat is Intellect. Intellect flask and food.
Secondary stat order: Spirit > Haste > Crit > Mastery.
Reforge Mastery then Crit to Spirit then Haste. Enchants focuses on stats as presented, but get Run Speed to boots.
For gems, I think the stat bonuses are worth it this time around, so red Int gems, orange Int/Haste gems, and blue Int/Spi gems.
Personally, I don't worry about specific gear pieces, just upgrade whenever possible.
So that's my current Holy setup for raids. It seems pretty decent so far.