Professions in WoW: what to take and why

Professions are not an “add-on”, but a source of income and part of the equipment. Let's sort the bundles by version.
Main professions
- Mining + Blacksmithing — equipment for warriors and paladins, stones and weapons.
- Herbalism + Alchemy - potions and bottles, stable income from raids.
- Skinning + Leatherworking - armor for horns, hunters, druids.
- Fabric + Tailoring — bags and “fabric” sets: bags are always on sale.
- Jewelry (with TBC) - stones that everyone needs.
- Enchanting - disenchantment and enchantments require an “additional” profession for materials.
- Style (from WotLK) - scrolls, glyphs, maps.
Additional
- Cooking — food for a “bonus to characteristics”, needed in raids.
- Fishing - for rare recipes and feasts.
- Archeology (from Cataclysm) - rare items and mounts.
What to choose
To earn money: herbalism + alchemy or mining + jewelry. For raids: alchemy (flasks) + cooking. For the first character: bags (tailoring) and enchanting - they always pay off.