Those abilities that provide a sizable benefit

So our question today is: what's your favorite or most important crafting item? I'm in the middle of leveling my paladin, and he's just now reaching the highest reaches of Engineering, which is a skill I've never leveled up before, but have always wanted to. I haven't gotten together the gold for epic flying yet (well on my way at level 73), but I did make normal flying machine as soon as I could. And my big goal with this character, other than getting him raiding Buy WOW Gold, is to make the Mekgineer's Chopper -- ever since we first saw it in the early days of Wrath, I've planned to get a character up high enough to make it. I know, I know, I can buy it, but for me it's a crafting thing -- I want to go out, find what I need to find, and craft it with my own virtual hands.

Any other crafted items that have you wanting to make something for yourself? Every week Matthew Rossi slaves in his kitchen over a hot stove, primarily because he needs something to nosh on while composing The Care and Feeding of Warriors, WoW.com's column about warriors. Also, he's chained to the stove. No no, don't ask, it's a long story.

Cooldowns. Those abilities that provide a sizable benefit to a character when used, but cannot simply be used over and over again due to a time-based limitation on their use. As far as I know, every class has a few. For warriors, being a two role hybrid, cooldowns can be further broken up into tanking and DPS related, with some overlap (the famous and oft-neglected Retaliation comes to mind as a cooldown that can be used in either role to some extent).and it's often the most basic and yet most easily overlooked aspect of warrior gameplay.