Jewelcrafting + Enchanting (on Main) because of the uber JC only gems. Enchant because extra min-max enchants on Rings.


Mining + Engineering.
Buy a repair bot to carry and pop it out when you're ready to sell while inside a dungeon.

Enchant + Tailor. You make tailor stuff, and DE them for your Enchant needs.

Herbalism + Alchemy. Once you get 300 Herb, you can get to 375 just running around Hellfire Peninsula. It's that easy.
Alchemy is a bit more of a pain, but I went for Transmutation Mastery.

Skinning & Leather-- I did not bother. PvP items > LW tradeskills, for less time.

Blacksmithing might be the same uselessness when 2.4 comes. Even with Primal Nether and Nether Vortex more obtainable, S3 weapon and armor is easier to get.