5 Exalted Reputations

Why not kill two birds with one stone by going for Ambassador of the Alliance or Ambassador of the Horde at the same time?

A fun way to raise a reputation to exalted starting at level 50 is with the Wintersaber Trainers. Unfortunately these quests are only available to the Alliance.

If you go to Frostsaber Rock in Winterspring (northernmost point) there will be an NPC named Rivern Frostwind on top of a very tall rock who will give you the quest Get Them While They're Young and then the follow-up quest They Grow Up So Fast. The second quest requires you to raise a Winterspring Cub, rewarding you with Reins of the Winterspring Frostsaber and exalted rep with the Wintersaber Trainers.

While you cannot keep the cub provided in the quest, you can purchase one from Michelle De Rum for 50g, who can be found inside the Everlook inn.

Keep in mind this quest must be done in 20 dailies but is fun and easy to fulfill.

Remember that all of the basic alliance/horde racial factions have tabards you can equip to gain reputation while running dungeons.

Several of the Wrath and Cata factions also have tabards you can use to gain reputation.

Even worth putting one on while doing some of your mount/pet/transmog runs.

edit: not sure why it's being down rated when it's factual.