Originally Posted by
Brightamethyst
Money - Some combination of mining/herbalism/enchanting. People always need mats, and this expansion rewards gazillions of worthless epics to DE. If you use a ton of flasks the extra duration from alchemy will save you money in the long run, but if you're not a raider it might not matter to you.
Useful - Probably engineering. It makes no money and doesn't help your guild at all, but things like gliders, portable bank and mailbox, loot-a-rang, etc, are still as useful as ever.