1TB Core USB 2.0 HDD + DESLock Desktop Hard Drive

Considerably cheaper than anything comparable from Amazon, this external HD has a blue LED to tell you it is working but is very quiet and unobtrusive. I bought the 1TB model to back up my photos and music files. So far I have filled less than 100 GB so there is plenty of room for more. The drive is formatted NTFS, suitable for Windows XP or later, and it worked straight out of the box. If you want to use it with Linux - as I do - you will need to install the ntfs-3g driver to allow writing to this filesystem. Or if you need to preserve your permissions and symlinks then you could reformat it to ext2, for example. That would also fox 99.9% of nosey parkers without having to use proprietary security software.