Here is the most efficient beginning build to Lvl 44.
Talent screenshots 20, 30, 40, 44*
Talent point distribution:
Lvl 10-11: Spirit Tap (2/5)
Lvl 12-16: Wand Specialization (5/5)
Lvl 17-19: Spirit Tap (5/5)
Lvl 20-24: Holy Specialization (5/5)
Lvl 25-29: Divine Fury (5/5)
Lvl 30-32: Imp. Renew (3/3)
Lvl 33-34: Healing Focus (2/2)
Lvl 35-36: Searing Light (2/2)
Lvl 37-38: Holy Reach (2/2)
Lvl 39: Holy Nova (1/1)
Lvl 40-44: Spiritual Guidance (5/5)
Reasons? See the following formula, starting at lvl 19...
5/5 Wand Specialization + 5/5 Spirit Tap = more Spirit Mp5 up time = less time drinking = more kills per minute = faster leveling.
Gearing:
As a general rule of thumb, you value spirit over all other stats other than spellpower/healing.
Spell rotation (based on level)
Shield -> Smite -> Mind Blast -> SW:P-> Wand until dead
Shield -> Holy Fire -> Mind Blast -> SW:P -> Wand until dead
This guide stops at 44 because when you ding 45 have 2 options. You can continue as Holy/Disc, or you can respec to 5/0/31 and finish the 1-60 as shadow.
Pros/Cons?
Holy/Disc - Easier to find groups to run instances as the dedicated healer.
Shadow - DPS, DPS, DPS!!!! Can still heal instances, but not mana efficient.