The Sons of Hodir is arguably one of the most important reputations in Wrath of the Lich King due to the items they offer. They're the only faction in Northrend that offers shoulder enchantments for PvE, in rare and epic flavors. Casters? Melee? Healers? Tanks? The Sons of Hodir have all of your shoulder enchants.
The quest chain to completely open up the Sons of Hodir rep grind is long. Really, really long. It's long in the good way, though. It's epic, and part of the chain is quite possibly one of the most fun quests in Wrath, and is as close to God of War as you're going to get in WoW. 'God of War in WoW!?' is what you're probably thinking. WoW Insider's answer to that? Yes. It's freaking awesome.