What is the ONE essential, 'can't-live-without' item in your wardrobe at the moment?

[MrsSeanBean]

I'll start off with this navy shrug from Monsoon. It's great over dresses, camilsoles etc but doesn't feel bulky or too warm. (Am self conscious about thin straps.)

Mine is this cardigan:

Here

It has perked up my jeans/dresses and have had lots of comments about it.