There are lots of ways to gear up at level 80 in the World of Warcraft but reputation is one of the most productive ways. The advantages to reputation items are that they can be earned solo if need be.
   To be honest, reputation can produce lots of good rewards for the persistent grinder. As a Hunter, you will want to make use of the various factions to gain some of their items and make yourself just a little more deadly. Time and patience is the only thing you need to get what you want.
   You have the ability to scavenge many items from the factions in Northrend like the Argent Crusade, the Ebon Blade, Frenzyheart, and Sons of Hodir. These are the main ones for the Hunter but you will have to need to work up each of them to get some of the better Hunter items because each faction has a large assortment of items. You will need to earn faction by doing quests, daily quests and you can gain some by championing a faction in level 80 dungeons by wearing their tabard.
   The Argent Crusade is the first faction we choose and the reason is that your weapon is the most important piece of equipment for you as a Hunter. Speaking of faction reputation, the Argent Crusade furnishes the best Hunter weapon with the Zombie Sweeper Shotgun that you can buy once you reach the reputation rank of honored. In the same way, you can grab the Polished Regimental Hauberk for a nice agility and hit rating boost and the Cloak of Holy Extermination at honored which makes a good Hunter cloak. Melee isn't really the Hunter's thing, but you can fill your melee weapon slot with something that will provide a useful stat. For now you can use this hauberk if you don't have anything better. Later, you will be getting your hands on some one hand weapons that will increase your hit rating from a couple of other reputation vendors.
   You are capable of doing many quests in this faction, which provide reputation. You can but the Tabard of the Argent Crusade from their quartermaster and earn reputation by killing in level 80 dungeons. Some of the higher reputation quests for this faction include the Imprints of the Past quest chain in Dragonblight which yields around 1000 total reputation once completed. You can find additional quests yield Argent Crusade faction in Zul'Drak, the Howling Fjord, Dragonblight, and Icecrown.
   The Knights of the Ebon Blade is the next faction you'll find a dagger here, which improves your hit rating. As one of the most important stats, hit rating should be increased every chance you get. A shoulder item will give a nice boost in agility, attack power and critical strike rating. An enchantment item will increase your critical strike rating and attack power for a head slot item.
   You'll need to do some of the quests located in the Shadow Vault so as to build your Ebon Blade faction. After that you can continue to work on faction giving daily quests or buy the tabard and grind it out in some level 80 dungeons. You can find reputation, which gives quests for the Ebon Blade in Zul'Drak and Icecrown. Parting Gifts is one good quest line for increasing your reputation with the Ebon Blade, which can be found at Shadow Vault in Icecrown. It yields a large amount of reputation through completing this quest chain. But in the same area, there are several other quests you can grab and do to increase your faction more quickly at the same time.
   The Sons of Hodir is the third faction you can earn a dagger. It increases your hit rating a bit more. You can choose a belt that will boost your agility and another enchantment for a shoulder slot item. The Sons of Hodir starts out aggressive so you will need to do the quest chain they look our men to boost your faction with them. After that you can find a number of daily quests available in The Storm Peaks that offer reputation with this faction and you can cash in Everfrost Chips to Calder and Relics of Ulduar to Lillehoff for additional faction. Everfrost Chips can be found as random spawns in northeastern Storm Peaks and Relics of Ulduar have a chance to drop off of enemies in Storm Peaks.
   The Frenzyheart and the Oracle are the last two factions. The former will provide you with some useful goods. When you become content to it, you make yourself very unpopular with the Oracle is its weakness. Both can be found in Sholazar Basin and you can begin the faction by doing the quest playing along ending with A Hero's Burden. Your choice in this quest will determine which faction you become allied with and which one wants to see you dead.
When you try to work on the Frenzyheart Tribe, they've a very nice trinket for Hunters to utilize that improves haste rating and increasing your damage output for 10 seconds as you slay an enemy that gives honor or experience. This is the only item they have that is useful for a Hunter but it can be a very good trinket for a while. Unluckily you have to be exalted to buy it or grind it. You will need to work on the daily quests for the Frenzyheart to build your reputation. It will take a bit of grinding to get your reputation up to exalted.