Now, as I suspect you know, I've moved on to raiding on my priest and so I've been working on healing specs for the patch. Especially Holy has changed quite a bit, and there's plenty of pitfalls where raidhealers may end up taking talents which don't support their raidhealing. Also, Disc has become a great tank-healing spec, and every 25man raid should include one, or look to recruit one.
Now, as I said Holy is ever more clearly the raid healer, and as such we've started eliminating everything that's not boosting your raidhealing and come up with this spec. There's a couple of talents most priests would gawk at, and most raid leaders too. Gheal has always been a staple of priest healing, and so people have always used talents such as Divine Fury and Improved Healing, but as we're specializing gheal is a spell that should be removed from the Holy Priest arsenal. Instead for spot-healing flash heal and renew are the tools to be used. But then why not take talents like Empowered Healing and Surge of Light? Because spot-healing still has a very low priority in raid healing. Both of these talents are optional, but you need to realize flash heal should be a rather small percentage of your healing done.
So then what's going to make up the larger part of your healing? Prayer of Healing is the new king being capable of putting out around 10k heal per target when glyphed, and should probably make up close to 40% of your healing done(preliminary numbers, depends on encounters also). Circle of healing is the quick-fix raidheal to be cast when off cooldown. Prayer of Mending should always be on cooldown as well. Renew is the fourth spell of choice, mainly for keeping up Holy Concentration.
A controversial choice is Spell Warding which serves to make your holy priests a bit less squishy on progression content. This is obviously something which can be dropped for farm content as is seen fit. The completely optional talents are as follows:
-Inspiration 3/3 which has some merit as it can proc off both PoH and CoH
-Healing Prayers if mana is an issue
-Surge of Light for some extra free spothealing with a good uptime since again it procs off your aoe-heals
-Lightwell which is situational although quite good if your raid knows how to use it
-Body and Soul an unconventional choice although with some potential synergy with the 4pT8 setbonus as well as some interesting uses f.ex. on XT-002 Light Bomb and Gravity Bomb
-Empowered Healing if you find yourself wanting to cast more Flash heals than you really should or using Binding Heal a lot(great ability, but way too situational to merit it).
Personally I'd probably pick up the last point of inspiration for progression content, healing prayers for mana longevity and lightwell to help with the healing when possible. Body and Soul may be a worthy option for one priest in the raid, though I don't see much reason for more than one healer to pick this up.
I'll hope to get some writing done on Disc spec soon to round this off.