I have and using:

Paladin - Engineering / Mining - Using the Eng Helm, Rocket Launcher, Repair Bot and Seaforium Charge.

Shaman - Enchanting / Alchemy - DE Everything making 20g min a day for nothing (DE Ogri'la Aegis once a day) and working on Ring Enchants - Alchemy making min 20g a day (Earth -> Water) and might work on Redeemer's Alchemist Stone

Mage 1 - Alchemy / Tailoring - Alchemy making min 20g a day (Earth -> Water) and might work on Sorcerer's Alchemist Stone - Wearing Spellfire Gear and might make Spellstrike Gear

Mage 2 - Tailoring / Herb - Wearing Spellfire Gear and might make Spellstrike Gear

Mage 3 - Tailoring / Skin - Wearing Spellfire Gear and might make Spellstrike Gear

All of them are at 375 except Engineering (369- working on it).

Professions take a lot of time... I remember spending 2 hours questing running instances, then another 2 hours afterwards sorting out all the mats, going to profession trainers and leveling them up. I would say, that at least 1/3 of my 17 days played to level was for my professions.

They also take a lot of gold to level ... but at the same time, if they help you at 70, then you'll kill mobs faster, which means finishing more dailies == more gold.

Only look at the BOP items for each profession and make sure that's what you want. If it's BOE, ignore it, because you can just have someone make it for you.