Here's an overview of the talents (as they exist on Beta now) for Holy Paladins in Mists of Pandaria. I do have some playstyle biases. This is from a max level PvE healing perspective. As well, I generally prefer passive abilities to active ones. I already have a lot of buttons to press, more buttons probably won't help me. So take my advice with a grain of salt.
Kurn has posted her look at talents and glyphs, which is an excellent overview as well.
In this post, I'll cover spending holy power and the first three tiers of talents.
First, a thought to how we will spend Holy Power in the expansion. There are essentially two styles.
Option 1: Build to 5, WoG, HS, WoG, now have zero HP.
Option 2: Build to 5, WoG down to 2 HP, then build back to 5. Always keep 2 HP banked for emergencies.
Now, Option 1 allows you to do a large amount of burst healing, for minimal mana in 3 GCDs. But you have to build back up to 5 HP every time. Option 2 is more or less our current playstyle, only you go 5 HP to 2 HP to 5 HP. The two HP is banked and only spent in a great emergency.
Both options do roughly the same amount of healing in the long run. All that changes is how the healing is distributed. In Option 1, the second WoG comes right on the heels of the first WoG. In Option 2, the second WoG comes much later than the first WoG.
I am a fan of Option 2. I don't think we will need to burst like in Option 1 regularly. A regular healing cycle like Option 2 is more than enough. As well, Option 2 allows you to burst in emergencies.
Tier 1: Speed Increases
Choices: Speed of Light, Long Arm of the Law, Pursuit of Justice
Speed of Light is a large speed increase on a long cooldown. Long Arm of the Law is a medium speed increase for a short time which you get every time you Judge. Pursuit of Justice is constant increase, that also scales with Holy Power.
My choice: Pursuit of Justice.
It's always on. A Holy Paladin doesn't need to Judge, so that would be an extra button. Plus, if you play with 2 HP banked at all times, your speed will be a minimum of 125%, and often 130%. That's more than enough to keep you moving out of the fire quickly.
Tier 2: Crowd Control
Choices: Fist of Justice, Repentance, Burden of Guilt
Fist of Justice allows you to stun twice as often. Repentance is proper crowd control. Burden of Guilt adds a significant slow to your Judgement.
My choice: Repentance.
Good CC is always useful when running instances. Burden of Guilt requires Judging, so that's out. Fist of Justice is useful, but stunning is often less useful in PvE. However, on specific fights, especially in raids where things are immune to CC, a shorter CD stun might be very useful.
Tier 3: Healing
Choices: Selfless Healer, Eternal Flame, Sacred Shield
With Selfless Healer, after Judging 3 times you get a free, instant, super-powerful Flash Of Light. Eternal Flame is an upgraded Word of Glorgy, tagging on a decent-sized HoT. The initial heal of Eternal Flame is exactly the same as WoG, so Eternal Flame is a straight upgrade.
Sacred Shield is similar to our old Sacred Shield, but built slightly different. To be honest, the old version was a bit confusing, and I think the new one is more straightforward. Sacred Shield is a "shield HoT". Every few seconds the shield refreshes itself to its initial value.
My choice: Sacred Shield
Selfless Healer requires Judging a lot, so that's out. Sacred Shield is something you just keep on the tank, and it will do its job, preventing damage nicely. Eternal Flame is a pretty good choice, but you know have to target EF more strictly than WoG. WoG you can just drop on anyone who is hurt. With EF, you probably want to target someone who will take more damage in the future, so you don't waste the HoT. Personally, I tend to just throw WoG around randomly whenever I have enough Holy Power. As well, preventing damage is usually a bit better than healing it, so I lean to Sacred Shield.
Link to Part II.