As a university student, my flash drive -or "memory stick" as we call them- has become my best friend. It takes away that stress of a virus eating up all your coursework, or your printer running out of ink. Most are very reasonably priced, such as the Maxwell 4GB USB flash drive.
I was surprised at how much work I could fit on there. I even used it when transferring all my files from my old laptop to a new one. It was quick, efficient and easy to use, no instructions needed. It's also small enough to just pop safely in your pocket or bag so that you can take it to work or uni with you. I'd highly recommend this to anyone, especially a student, it just takes away the stress that work loads already carry and allows you to focus on the work itself, rather than losing it.