Comment 17 for bug 99538

I have had the same problem with my Western Digital 250GB External HDD. Although the solution that causes the device to "Unmount" rather than "Eject" lets you remove it without being root, the WD HDD does not 'click' when removed which indicates that it has been properly removed and the HDD has come to rest (whereas the unmounting option just stops it communicating with the PC rather than actually removing it).

When I run eject sdc1 I get the following back:

umount: /media/My Book is not in the fstab (and you are not root)
eject: unmount of `/media/My Book' failed

However, if I run sudo eject sdc1 then the device is not only removed but 'clicks' indicating that it has been properly removed. For the moment I am just using the terminal to remove it, however you should not need to be root to remove a USB device, there's no reason.

Right-clicking on the drive in Kubuntu Edgy 6.10 removed it properly (same as sudo eject sdc1 in Feisty), this was not a problem in Edgy.