External storage is nice but there are far more options for you if you need to work with networked systems. NAS is the answer to many of the issues I faced when it came to external storage options.
Western Digital has a My Book World Edition II that will allow you to store files from your networked PCs and laptops all around your house, into one location. The terabyte of storage is split into two 500GB hard drives and it uses WD Anywhere Access which many say is "trouble-free" software, and superior to other packages.
The nice thing about NAS is that you don't have to have the one computer that has your storage device connected, powered up. NAS allows you to be free from that and simply connects to your router so that you can use your laptop and wireless card to access your files from anywhere!