Arcane resistance

Arcane is primarily used by Mages and Druids. It has long been one of the least used resistances, but this seems to have changed with the raid content in The Burning Crusade. Gnomes and Blood elves, having an affinity for arcane energies, benefit from permanent Arcane Resistance as a racial trait. Arcane resistance is not necessary in Karazhan but can be used by an "offtank" on The Curator. It is likely that it will be needed in later TBC raid instances due to the abundance of Arcane resistant gear available.

Resistable spells

 * Druid: Moonfire, Starfire
 * Hunter: Arcane Shot, Flare, Hunter's Mark
 * Mage: Arcane Missiles, Arcane Explosion, Counterspell, Polymorph, Spellsteal

Example items with arcane resistance

 * Item list from Wowhead.com
 * Blue Dragon Mail
 * Cloth:
 * Soulcloth Embrace: 110 AR, 78 Stam, 48 Int, 36 Spi, 3 pieces: gloves(1 yellow 1 red, 3 Int), shoulders(1 yellow 1 red, 3 Int) and chest(1 yellow 1 red 1 blue, 4 Int): 16 spell hit rating bonus for 3 pieces
 * Arcanoweave Vestments: 110 AR, 115 Stam, 9 mp5, 3 pieces: boots, wrists and chest: 16 spell hit rating bonus for 3 pieces
 * Leather:
 * Enchanted Clefthoof: 100 AR, 84 Stam, 3 pieces: boots(2 blue, 6 AP), gloves(2 blue, 6 AP, legs(3 blue, 8 AP)
 * Mail:
 * Enchanted Felscale: 100 AR, 84 Stam, 3 pieces: boots (2 blue, 6 AP), gloves (2 blue, 6 AP), legs (3 blue, 8 AP)
 * Plate:
 * Enchanted Adamantite Armor: 140 AR, 96 Stam, 4 pieces: belt (1 blue 1 yellow, 3 dodge rating), boots (1 red 1 blue, 3 dodge rating), chest (2 blue 1 yellow, 4 hit rating) and legs (1 red 2 blue, 4 dodge rating)