When it comes to picking factions to grind, I keep in mind a few variables: gear I can use for a specific character, supporting recipes for their professions, and vanity pets. I mean, would I have ground out Sporeggar rep to Exalted had there not been a [Tiny Sporebat]? No way!
With that criteria in mind, I made a list of the Wrath of the Lich King factions known to have reputation-based rewards.
- Argent Crusade*
- Frenzyheart Tribe (faction at war with The Oracles)
- Kirin Tor*
- Knights of the Ebon Blade*
- The Kalu'ak
- The Oracles (at war with the Frenzyheart Tribe)
- The Sons of Hodir
- The Wyrmrest Accord*
The above factions with a * allow you to purchase a tabard at Friendly. When worn in a dungeon, that tabard allows you to earn rep with that faction, regardless of the reputation associated with the dungeon in which you are fighting. A nice way to encourage folks to branch out into a variety of dungeons, rather than living for a month in one just for grinding rep.
In addition to the above factions, if you are an engineer interested in acquiring the plans to make a [Mekgineer's Chopper]/[Mechano-hog], you will have to grind 4 factions you might otherwise skip maxing out: Horde Expedition Exalted (The Hand of Vengeance, The Sunreavers, The Taunka, and Warsong Offensive) or Alliance Vanguard Exalted (Explorers' League, The Frostborn, The Silver Covenant and Valiance Expedition). As of right now, I haven't seen any details on faction-specific rewards for these individual factions. There is a quartermaster for the combined grouping, however, the rewards are not that interesting other than the motorcycle. But as with anything not yet live, that remains to be seen.
The biggest surprise to me after reviewing all the reputation rewards was the lack of Blacksmithing, Alchemy, and Enchanting recipes from faction grinds. I'd gotten quite used to making my druid enchanter chase after a variety of factions to round out her enchanting repertoire.
Details on specific faction rewards after the cut.