This time I'm going to go over what may be my real obsession, professions. I'll talk a bit about the secondary skills, as well.
Hunters benefit reasonably well from leatherworking, engineering, jewelcrafting, alchemy, and enchanting. Inscription is useful to a lesser extent, but the offhands aren't really focused on a hunter, so you're probably better off buying your glyphs, unless you're doing inscription for the money. Blacksmithing produces some mail, and some useful weapons, but not enough to warrant taking it yourself. Tailoring makes bags, but the rest of what it produces isn't likely to be useful to you. If you specialize your leatherworking, dragonscale is the mail specialization. Whether you go goblin or gnomish engineering is mostly a matter of whether you want the sapper charges or the gnomish gadgets. Alchemy specialization depends more on what you want extras of.
Leatherworking is a good choice for making your own armor, and is fantastic for self-sufficiency while leveling. It will produce armor kits for you, and give you bracer fur linings, even after you upgrade beyond what you can craft. Several of the crafting bags are made by leatherworking, as well. If you specialize, Dragonscale makes mail.
Engineering is good if you want to make your own ammunition and/or weapons (guns) while leveling. It also produces an array of gadgets, trinkets, and explosives which can assist you while soloing. (The goblin landmine can render you a bit over-powered in the 30s and 40s.) Goblin and Gnomish are probably equally useful, and the difference is negligible at the upper levels. Engineering also makes scopes, which come in damage, crit, hit, and haste flavors. (You'll have to farm Molten Core for the hit scope schematic if you want it, though.) Seaforium charges aren't as important in Northrend, but going into Dire Maul (North) you'll probably want them to get to the last couple bosses, as well as in Shattered Halls to avoid the slime tunnel. (Seaforium will also open chests and lockboxes.)
Jewelcrafting will make you, at lower levels, mostly rings, necklaces, trinkets, and little statues that will heal you. The statues that heal you are pretty awesome - it's like a bandage you don't have to channel yourself. At the upper end, you'll get some of the best gems, and be able to make some awesome rings and necklaces. Gems are also perennial best-sellers on the auction house, for a ready source of cash.
Alchemy provides healing potions, mana potions, elixirs, flasks, a few miscellaneous concoctions, transmutes, and a handful of trinkets. The trinkets (at least a philosopher's stone, initially, and later upgrades of it) are required for transmutes - they also have decent stat boosts, and enhance your regenerative potions. Alchemists get potions specific to them which act like a rejuvination potion, plus give a random elixir buff. Some alchemy products sell well at auction. Specialists have a chance to create extra items.
Enchanting is useful because you can crunch all those greens you get while questing to either buff your own armor or sell for cash. Enchants can be put on scrolls and auctioned now, so it's a little easier to make cash without hanging out in town, but scrolls don't sell as readily as you might think. (It's a paradigm shift that hasn't quite happened.)
The gathering professions - skinning, mining, and herbalism - are easily paired with a crafting profession to provide materials, or can be used as a source of income. Mining and herbalism are both more lucrative than skinning right now, although arctic furs sell very nicely.
Cooking, Fishing, and First Aid are all useful to a hunter. Don't sell your cloth until you max that type of bandages. (I know, I know... wool is insanely overpriced in the auction house, but you can get money much more easily, later, with the oodles of mageweave you'll be getting.)
With the changes to out of combat mana regeneration, hunter mana regen is even worse than it's been in the past. So while you're probably going to be spending a bit of time in Viper, you're also probably going to be drinking quite a bit, especially if your health is down, too. In other words, you're going to be eating a lot. Cook your food for buffs; eventually you'll be able to make pet buff food, too.
You can talent your pet to not need food often, but sometimes it's still faster to just toss your pet a piece of food to make him happy. Fishing can both give you ready pet food for several popular pet families and give you access to nice buff food. You can fish anywhere at any level now - you may not catch anything useful, but you can skill up fishing wherever your fancy takes you now.
Next up: pets. (Yes, pets. You're still a hunter.)