Armor
IconSmall Druid [Mark of the Wild] / [Gift of the Wild]: +750 @ max rank (1050 fully talented with Improved Mark of the Wild), stacks with other armor buffs.
IconSmall Paladin [Devotion Aura]: +1205 @ max rank, Improved Devotion Aura (Tier 4 Protection, 3 ranks) raises armor bonus to +2008.5. Each paladin can only have one aura active at a time.
IconSmall Shaman [Stoneskin Totem]: +1150 @ max rank (1380 fully talented with [Guardian Totems], a tier 2 Enhancement talent with 2 ranks), each shaman can only have one active Earth Totem at a time.
[Gift of the Wild] (from [Drums of the Wild]) - Identical to druids' untalented max rank [Gift of the Wild], item is crafted by leatherworkers and usable by any level 80 character.