Best things I know with engineering!

This profession is a pain, some claimed that it's not good enough for PvE, but what the heck, it's their loss!

Hand-Mounted Pyro Rocket: Best glove enchant available, suck on that!

Parachute(Cloak enchant): best cloak enchant is +22 agi, this one is +23... suckers ;)

Nitro Boosts: Rocket boots are just awesome, whatever you're doing! Running from Dalaran AH to BANK = win, any PvE situation such as doing tentacles on yogg-saron sprint and win!

Dalaran AH: Best thing I know so far, never actually have to teleport anywhere else!

Wormhole: It takes you right outside ulduar, AND coliseum! Only disadvantage is the cooldown, 4 hours, and don't try teleport "underground" ... not funny.

Jeeves: Forgot something in your bank? bags full when out farming? BANK IT/VENDOR IT!

Saronite Arrow Maker: Hunters best friend, make your own arrows... OH MY GOOOOOD!

That's just a few things with engineering that j'adore!

The infamous underground!