When people ask "what is the best race for a " they are really asking about racials; the bonuses each race gets and how these work with the hunter class.
It's important to note that racials are not balanced, and have never been balanced. This is not a QQ entry, its just a basic listing of the racial as they exist in the game. Keep in mind that at best these racials add maybe 1% to a dps total. Play the race you like the best for whatever reason you have. Both my hunters are at the bottom of their factions for racials and I'm always one of the top dps in my raids.
Worgen have two awesome racials that make them the clear winner for Alliance hunter racials:Viciousness and Darkflight.
The 1% crit gained from Viciousness is a really nice dps gain across the board for hunters, and unlike the dwarf ability, worgen gain this regardless of what weapon they're using. Added to this killer dps gain is Darkflight, a highly handy raiding ability.
Draenei Space goats come up next on the Alliance end, with Heroic Presence and Gift of the Naaru. The heal is nice but the extra 1% hit is almost as good as the worgen's 1% crit. Plus if you end up over on hit rating you can reforge a bunch of that away.
Dwarf Gun Specialization is starting out this xpac worse than ever with a serious lack of epic PvE guns. Stoneform has the occasional use for survival but doesn't really add too much to the bottom line.
Humans have nothing really great for hunters. Every Man for Himself can be useful at times, but meh
Gnomes cannot be hunters. Thank god for small miracles.
The Night elf racial Shadowmeld doesn't really help your raid kill bosses, so about all elves have going for them is Wisp Spirit. Considering the number of night elf Legloas' out there in the game it seems somehow appropriate that elves' racial should only work after you kill them.
Orcs lead the horde pack brining both Blood Fury and Command to the table, a brutal combination of pure dps racials.
The 5% pet damage from Command is obviously amazing for BM hunters, since it applies to Kill Command, but keep in mind that even SV and MM pets are doing thousands of DPS these days. Add to that over a thousand attack power usable twice a fight (in conjunction with Rapid Fire) and the fact that none of their racials are dependent on a specific weapon, and orcs lead the Horde in hunter racials.
Troll Trolls, once the laughing stock of warcraft racials, now sport Berserking and Bow Specialization making them a strong choice for a horde hunter.
Goblin Both Time is Money and Rocket Jump are valuable and desirable PvE racial abilities.
The benefit of 1% haste is a bit variable; it's always good, but since the value of haste fluctuates heavily based on spec, gear and the Moon in Aries, sometimes it's great and sometimes it's just okay. Rocket Jump, like any movement-boosting ability, can be life-saving in a progression raid. Not to mention it's just cool.
And so ends the dps portion of our discusion on Horde racials.
Blood elf Blood elves have Arcane Torrent, which nets them an itsy bitsy bit of focus that technically adds an itsy bitsy bit of dps. That's about all they bring to the party.
Tauren The base health increase from Endurance can be far more useful then War Stomp stunning mobs for a boss fight.
Undead Will of the Forsaken and they just look cool.