I'm leaning on Holy Shock
The holy paladin signature heal, Holy Shock, is so strong and cheap that you really have to use it. It's a different feeling to have a heal that we use on cooldown, since the old version of Holy Shock was so weak. I use Holy Shock as often as possible, and the Daybreak talent helps bolster the number of times I can use HS per fight. Not only that, but Speed of Light ensures that casting Holy Shock yields a benefit of some sort, creating synergy between our spells. While Infusion of Light used to tie Holy Shock and Flash of Light together, we never really had a reason to cast either spell. Daybreak, Speed of Light and Infusion of Light are all designed to capitalize on Holy Shock's potency to ensure that they remain relevant and useful.
Holy Shock also grants us holy power points, which lets us use the free and instant heal, Word of Glory. With Holy Shock being so cheap and powerful and also giving us access to another free heal, you actually save mana by casting it more often. Word of Glory has been nerfed a few times because paladins were leaning on it too much, but it's still a decent heal and really the only way we can burn our holy power effectively. The one thing I'm really missing (and looking forward to once Cataclysm goes live) is a good way to track Holy Shock's cooldown. It's a paradigm shift for us, and I can guarantee you that proper use of Holy Shock is going to be an important piece of paladin healing. Do we use our potent HS on the DPS who pulled aggro, or do we use it to top off the tank? I have had good luck simply using Holy Shock on whoever needs healing at the time, and then following up with a Speed of Light-infused Holy Light.
A tale of two heals
Paladins have healed for the past few years of content using only a pair of heals. Those heals are two brothers with little in common, except for the fact that they both made our hands shine with a golden glow. Flash of Light was weak but nearly free, while Holy Light was fast and powerful. At least, that's what I thought they felt like until I start healing in Cataclysm. Wielding these spells feels so different from how we use them today that you're better off forgetting what they do now and relearning them from scratch.
Holy Light is your auto-attack heal. It really fills the niche that Flash of Light resides in today. You can cast it nearly continuously, but don't expect for it to be fast enough to heal the entire party or powerful enough to keep up a tank under heavy damage. It's really just there so that we'll use more of our global cooldowns. You can heal through a dungeon using it primarily, but you'll really start to feel its weaknesses when your entire group takes damage or your tank gets slammed. Holy Shock helps to augment its weakness by giving you a bit of bursting healing every few seconds, but it's often not enough by itself.
Flash of Light, on the other hand, simply doesn't quite fit into its new role yet. It's meant to be our emergency heal, when we trade mana for speed and potency. It's incredibly fast, but unfortunately, it's just not powerful enough to warrant continued use. While it's far faster to cast five FoLs than it is to cast five HLs, you're better off using Light of Dawn or Holy Radiance to heal your group and then using a bigger heal to keep the tank alive. Flash of Light needs to have its potency increased to the point that it's truly an emergency heal-massive healing for a massive cost. Right now it's just too bland to find me using it regularly.
I know I said it was a tale of two heals, but we actually got a third one in Cataclysm. Divine Light is the de facto tank-healing spell and matches up the best with today's Holy Light. Its mana cost and slower casting speed do prohibit us from spamming it exclusively, though, and it's not a great choice for healing your raid. It's actually reasonably mana-efficient, but only if most of the healing goes to use. Tanks will be our primary targets for Divine Light, or we can use it in situations where we need higher HPS than Holy Light can allow but we can't afford to use Flash of Light to cover the gap.
Our new toolbox is exciting
Light of Dawn is incredibly fun to use, but only when it actually works. I've been learning how tricky it can be to target a cone correctly, especially when on the move. I have really been enjoying trying to position myself to maximize the LoD heal, although it made me come to a painful realization. Light of Dawn is most effective while our targets are at a distance, while Holy Radiance is only effective while our targets are nearby. The only real way to use both would be to stand with the melee group and then use LoD to try to capture as many of the ranged players as possible, but it feels like an unlucky angle on the cone would cause someone to die pretty quickly.
The other awesome thing about paladin healing is that we don't have to heal ourselves anymore. Both LoD and Holy Radiance affect the casting paladin, and the talent Protector of the Innocent makes sure that we're getting healed any time we're healing someone else. Think of it as a mini-Beacon of Light on yourself at all times. This would've been a godsend on fights like Marrowgar or Festergut, and I am so glad that Blizzard added this unique treat to paladins. It makes us far more resilient to incoming damage and helps solve the problem of too many people taking damage without enough GCDs to save them all. One heal can touch three people now, with Beacon and PotI used in tandem.
The Light and How to Swing It (Holy Edition) helps holy paladins become the powerful healers we're destined to be. Learn the ropes in Holy 101. We can help you keep a tank alive, heal a raid when necessary and beat the global cooldown. Tanking is a job, DPS is a craft -- but healing is truly an art.