Something everyone should take around with them everywhere they go is a USB Toolkit, featuring a small number of important applications and tools which fit comfortably in your pocket or on your keychain. Have you got a USB Toolkit, and what have you got on it?
I've divided mine into two directories - Windows apps, and Linux apps. In each of them, I have some basic portable software such as Pidgin (with OTR), a TOR browser, WinRAR, a SSH client, a secure erasing tool and even CCleaner
These tools come in handy when out and about, using public computers or just machines which don't have the basic software which you need.