Are you in it for the money?
The first question you should ask yourself is, “can I afford the profession of my dreams?” If you’re working on your first toon or starting fresh on a new server, you may very well benefit from putting off a crafting profession until the later levels. Taking two gathering professions and auctioning all of your herbs, leather, or ores will definitely pad your pockets considerably. In addition, some professions like Enchanting and Engineering are very costly, and provide little benefit until much closer to end game.
Do you enjoy crafting?
For many players, this is a big part of the enjoyment they receive from the game. Farming materials, creating gear for yourself, alts, friends, and guildies can be a really fulfilling pastime. Having a little extra to sell also isn’t bad for the bank account. It is definitely not, however, for everyone. If you can’t imagine kicking back on the shore of Tanaris with some good music and a whole pile of Turtle Scales, a crafting profession may not be for you. There is absolutely no sense in spending your $15 per month in order to writhe with misery over a pile of skins and thread. On the flip side, you may have been warned off of Engineering, since so much of what you create is only useful to yourself, and the costs far outweigh the auctionable benefits. However, Engineering is just plain fun, so if blowing things up sounds like your idea of heaven, by all means, pick up that wrench!
Gotta have it!
Is there something you can only get through mastering a particular profession? As much as the developers try to keep the professions balanced, there has always been - and probably, will also continue to be - one profession that benefits players and their raids more than any other. If you don’t mind dropping and leveling up often incongruous choices on a fairly frequent basis, you may find yourself participating in the “min-max profession of the month” club. We’ve seen Priests with Leatherworking in order to make use of the Drums, Shaman with Enchanting for spellpower-boosted rings, and currently, Jewelcrafting appears to be at the top of the heap for its offering of epic gems.
Inscription still offers unparalleled shoulder enchants, while most, if not all, of the offhand items have become bind-on-equip. Tailors can only use the best spell thread on their own pants, and likewise with the cloak embroideries, while Leatherworkers make leg armor that only works on their own pants.
The RP Question
If you spend your time on a Role-Playing server and enjoying RPing, your choice of profession will have some impact on your character outside of just an easy supply of potions, scrolls, or bullets. Think about your character’s back story, and which profession fits into whom you feel he or she really is.
Some races lend themselves to certain professions, and may even have a racial bonus for that job. For instance, Humans, Dwarves, and Orcs get a bonus to certain weapon skills, so you could make a case for a toon of those races taking Blacksmithing and specializing as a Weaponsmith. Likewise, it makes sense that an ancestor of failed Gnomeregan should have an affinity for Engineering. The cultures of both Tauren and Night Elves lend themselves to Herbalism, although only the Horde race receives a bonus to the skill, and one can easily imagine the shadowy Undead experimenting deep into the night with Alchemy.
Of course, class figures into the decision heavily, as well. Although Rogues no longer have to brew their own poisons, they do still enjoy mixing up a batch of Free Action or Swiftness Potions. Likewise, Hunters and Druids understand the importance of beasts in our world, and will take both meat and skins from their kills in order not to cause waste.
It’s your party!
In the end, you are the one who will be spending your time in game on your chosen professions, so you are the only one whose opinion matters in this area. Choose something that you like doing, that you know you will enjoy, and that will help to benefit and develop your character. If your choice happens to play upon a racial bonus, consider it simply a happy coincidence.
Finally, keep in mind that many of the gathering professions now provide an added bonus to your character which levels up along with you. Herbalism’s heal-over-time spell, Mining’s bonus to Stamina, and Skinning’s additional chance for critical strikes are all extras that most toons could really put to use. The important thing is that you are looking for a profession that enhances your character and provides enjoyment, not an experience that reminds you of a real-life job.