If you're not min-maxing at the level cap, your best bet will generally be at least one, if not two, of the three Gathering professions, Skinning, Mining, and Herbalism. If you do decide to take a crafting profession, choose the gathering profession that meshes most closely with it (i.e., if you take Leatherworking, grab Skinning, Engineering, grab Mining, or Alchemy or Inscription, take Herbalism.)
If you want to make money using a crafting profession, the best choice before the cap will be Inscription, as the Glyphs you can produce as early as level 5 will be used even by level 80 characters, providing you with a constant market.
If you want to produce things you yourself will use on a regular basis, Engineering provides fun toys, and trinkets at much lower levels than they'll be availiable as drops. Leatherworking allows you to make your own armor, but drops and quest rewards will, for the most part, be better than what you can craft - at least until the Cataclysm expansion releases. Alchemy will allow you to make a variety of useful consumables, but in general, you will have to make many more than you'll be able to use as you level, and there won't be much of a market for what you craft.
Enchanting is a viable option as well, and you'll be able to enchant your own gear as you level, which is handy.
Realistically, until the +Stat bonuses at 400+ skill come into play, there really isn't a 'best' or 'most useful' profession. There are a few that will be much less useful to you as a hunter, such as Blacksmithing and Tailoring, but for the most part, you should be fine picking out whatever you find fun.
The only other major note worth making is that each of the three gathering professions provides a free 'passive' boost as well. Mining will give you some extra Stamina for free, Skinning will give your character increased critical strike chance, and Herbalism will teach you Lifeblood, a free Heal-Over-Time spell you can cast on yourself on a short cooldown. The crit from Skinning especially should be very handy for a low level hunter, though the other two perks are nothing to sneeze at either.
Best Answer
It's possible, but tricky, to do it if you happen to be:
The trick is to aggro Razorgore, then jump from a ledge near the Grethok the Controller to a balcony. Once on the balcony, Razorgore will continue to attack you, but Grethok will call off the alarm, preventing adds from coming in to kill Razorgore:
As long as you quickly kill Grethok and the other two orcs, and stop controlling Razorgore once you hit ~25 seconds left on the Mind Exhaustion debuff, you can destroy the eggs with impunity and take Razorgore down.
Hunters, Goblins, and Engineers
To jump to the balcony, you need to use:
The YouTuber Shopebay1 put out two videos demonstrating the basic premise.
As a hunter with Disengage and a parachute:
As an engineer with Nitro Boosts:
Note that I found trying this with the Nitro Boosts to be extremely frustrating: you only have a few seconds, it's prone to failure, and it has a three minute cooldown, meaning if you don't make the jump it's a wipe.
Demonology Warlock
Demonology warlocks have it easy. Before pulling Razorgore, make the jump using Demonic Leap. Once on the balcony, summon a Demonic Circle. Then, pull Razorgore: once you're in range of the Demonic Circle, pull one of the orcs and teleport. Then, follow the same strategy described above and demonstrated in Shopebay1's videos.