The Tier sets are definitely going to be used for Transmogrification in the next patch, 4.3. Blizzard is presenting daily on the official website the class tiers.
Here are the Hunter tier sets that have the best looks, Tier 1 and Tier 6.
Tier 1, the Vanilla tier, first tier, can be obtained from Molten Core from the bosses there and some off pieces like belt, bracers that drops from the mobs inside, those being bind on equip items.
Tier 1
Incredible good looking, like the armors from the Gothic 1 and Gothic 2 games by Piranha Bytes. At this point, Molten Core can be soloed as beastmaster in even less than 30 minutes.
Tier 6
Tier 6 is the last Tier of the Burning Crusade expansion and the best looking with the best advanced graphics, the shoulders and the helmet having some sort of eyes that are constantly moving.
Ther gear can be obtained from Black Temple (Illidan raid) and from the raid called The Battle for Mount Hyjal (Caverns of Time). Both raids can be soloed by two players or three being recommended. A tank is required, death knights with blood spec is the best choice.
The other tier sets are the Tier 2, dragon looking, Tier 3 and 7 sharing almost the same looks, pretty bland, Tier 4, the demon stalker not really hunter style. Tier 5 having some nice effects but the helmet is really awful, the ones from Wrath of the Lich King or Cataclysm are not even worth to mention.