I have a Seagate ST380817 (80 GB SATA) in an external Mediasonic HD2-SU2 (USB hard drive enclosure). It works in Linux but I can't unmount it as a user. KDE/HAL mounts it as root. A hack solution is to add an /etc/fstab entry. I'd rather fix the HAL configuration to let users unmount it. My USB memory key mounts and unmounts fine as a user.