Lord, where to start ...
Given the week I've just been through, I'd have to say Organisational Skills AND Professionalism. Oh, and multi-tasking (& I'd like to shoot the person who invented THAT one

)
And don't you all just wish other people would own responsibilities? How often do you find a job doesn't get done until you pick it up because of "Oh, it's not (in)my job (description)." I could happily have throttled two of my colleagues this week ...
Oh, Gem, get off that Rant Box again (I've been on & off it all darn' day)