So what about Professions in vanilla...

[drabus]

...which ones are the most useful and in demand for guilds?

I've always been a gatherer rather than a crafter, but I think I'm going to pick three different professions (one for each of my characters) to actually make stuff. It seems like there may be more demand in a private server.

Am I mistaken there?

Which professions do you think would be the most helpful to a guild or to the server?

[Aquane]

the most helpful professions are gonna be swordsmith and macesmith(since almost nobody else will go those routes), alchemy(for arcanite), and tailoring(for mooncloth), and enchanting is always nice to have around, and not in that order

theres gonna reliably be some armorsmiths and axesmiths, who will probably the the GM of a guild or an officer in it, about half of pvpers will go engineering, and people will go their own way with leatherworking, and it'll turn out that you'll reliably be able to find someone to craft black dragonscale, stormshroud, and devilsaur armor
you can never have enough tailors and alchemists for cooldowns; its also always nice to have a maxed out enchanter hanging around in org or IF

[Drain]

Enchanting. It's the most frustrating and painful profession to work, yet every player at max level needs one to enchant their equipment. You'd be very valuable to a guild with it at max, especially if you take the time to get some recipes. It would easily pay for itself in the long run, as you can charge fees just to take mats and enchant people, which is money for nothing for you, but getting it there in the first place is very difficult. It's a huge money sink to work this profession. It's a very long term choice, doing nothing but wasting money until it's at max skill. It's better for alts when money is no longer a problem and you can throw things away without a consequence to feed it. But if you're poor, stay far away.

Alchemy. Not only can you make good money selling the high end potions that every max level player and guild wants, but you can make money transmuting arcanite. If I remember correctly, this was a CD that can only be done every 24 hours. So people would pay you to use your CD for them to transmute their arcanite, which is needed for many of the high end crafts. While working it up, you could sell potions, or use them yourself. This profession can be applied to almost any class, since anyone can chug buff potions.

Blacksmithing. It has unique paths, meaning different players with this can't all craft everything. Not only would they have to trade crafts with each other, but you can sell high end gear to players without it. This profession is difficult to work, very grindy, but can make a lot of your own gear as a Warrior/Paladin on the road up. It's a big sink of metal and demands extreme farm time for ore, but can make the money back by selling all the unwanted crap in the auction house. All the stuff you waste your days and nights crafting are at least tradable, so they can be sold. But it's very grindy. If you don't want to spend entire days farming ore, you should probably stay away.

Tailoring. Bags. Bags. And more bags. Good money all the way to max level and at max level selling the biggest bags. Everyone needs bags. It can make some decent cloth too, but casters aren't as gear dependent as physical classes, so there was never as much a demand for cloth gear. Many players just neglected their gear to save money, since it wouldn't improve their leveling as much as a physical class gearing up would. On a Warrior or Rogue, wearing the best gear every bracket is important. As a caster... you can level with whatever crap the quests give you. So try to focus on making bags for skill whenever possible. Bags will always sell!

[Hatson]

Definitely best to ask your GM, or commune amongst your friends that you will be playing with. See what everyone else is doing, might help make a decision.
However, if you're alone.. Well. Alchemy (transmutations) and Enchanting are quite sought after amongst trading.
But then again, the gathering professions are always the fundamentals, whether it be for your own use or selling.

[Drain]

WTB Arcanite Reaper.
^ Used to see that in trade chat everyday.
Also: Looking for someone that can chant Crusader.

[venven]

Banker.

[Thrashing]

To help a guild or server:

Any crafting profession is a big help, especially if you manage to obtain a rare random Molten Core boss drop or world drop recipe, or the harder to get reputation recipes.
There are always many players that roll Alchemy and Tailoring, due to Arcanite and Mooncloth being incredibly useful. There's usually a lesser amount of Leatherworkers and Blacksmiths.
Enchanting is also a very good profession, although I wouldn't call it a crafting profession. But personally I feel that to be a succesful and sought after enchanter, you need to be very dedicated to grinding reputation and rare drops. Most of the enchants people will search for are fairly difficult/time consuming to obtain (think of: crusader, greater stats on chest, agility on weapons, etc).

For personal benefit:

Gathering professions are one of the better ways one can make gold, and it requires less dedication than crafting professions to have a steady gold income from simply farming herbs, ores or leathers.
Engineering is a crafting profession, however it's more based around gadgets and explosives for the player itself than for crafting for other players. Engineering does not have a lot of recipes that are sought after by other players. However Engineering probably the most useful profession to help with PvE or PvP encounters.

[Avshar]

i will probably go for herbalism/ enchanting..

[ricprimus]

Definitely enchanting and tailoring for my lock, many of the recipes from reputation are quite useful, along with being cash cows. My second toon will be a druid with skinning and tribal leatherworker since I hate buying leather to make bags.

[drabus]

Thanks for the great replies. I think I know where I'm going to go with my professions...