The Holy-focused Tier 6 Paladin set, Lightbringer Raiment includes a 2-piece set bonus that increases the critical strike chance of the Paladin's Holy Light spells by 5%.
Patch changes
Patch 4.2.0 (28-Jun-2011): Holy Light mana cost has been increased to 12% of base mana, up from 10%.
Patch 4.0.6 (8-Feb-2011): Holy Light mana cost has been increased by approximately 10%.
Patch 2.4.2 (2008-05-13): Flash of Light and Holy Light will now work properly with castsequence macros.