@ snommism: I'm Armormech so I'm finding it pretty useful for my own toon since I've been able to craft exceptional (now augmented) Rakata belts and bracers which has really helped me out for endgame content.
Even better is now I can craft orange items with augment slots for my fellow guild members. Mav's gotten me a schem for a smuggler chest piece he wants so that's the first thing I'll be working on for him.
Armormech is VERY useful... so's Synthweaving which is just the Jedi variant of Armormech... oh and Cybertech ends up being useful too for folks who like to sell speeders and the ship modifications.
Of course you can't forget Biochem which is nice and useful for endgame content thanks to its reusable medpacs, stims and adrenals.
Also, about missions, I make sure to complete every single mission on a planet before I leave unless it's a heroic and I don't have a group or can't be bothered with a pick-up group. Then I abandon those since they're redo-able anyway. Basically I drop any mission which resets on a daily basis.