(And a special thanks to those who contributed ideas via !)
: Any self-respecting geek should have some form of portable drive. And not just one or two--you should have an entire collection of them. You should know then how to partition your flash drive properly. Your flash drives should contain a collection of system utilities and perhaps a Linux installation or two (hat tip to Joe S. on for the tip!).
: Having a box of miscellaneous cables is great. It isn't only useful for finding a spare in case a cable goes missing, but you'll also have cables for just about any unforeseen circumstance. You'll probably find the box will be mainly made up of Ethernet cables, but this is good for wiring up your whole house.
Don't forget to put a cable in your bag (be it a USB or a specific charger cable) just in case your latest cool gadget, laptop, or otherwise runs out of juice, or needs hooking up to a PC.