Power cords and other gadgets

It is quite amazing how I've become so dependant upon electronic gadgets. My power cord for my laptop that I use for all of my writing endeavors was frayed, and finally the tiny section that was bent over and over again became weak and the exposed wires started to fray, and of course no matter how I tried to position the cable, it just wouldn't charge my laptop, which has my current WIP and the outline for the next. Needless to say, I can't do without my laptop, and my laptop can't do without a functioning power cord.

As a writer, what items in your arsenal are so crucial that you just can't do without?