LaCie makes a line, as do Maxtor, Buffalo, Granite, Tritton and others.
The biggest issue by far for Mac-only shops is that they usually require a PC in order to set up and to do major maintenance like upgrading the drive's firmware.
Even though they advertise "Compatible with Mac OS X" that means that they are file read and write compatible, NOT that all possible functions can be done from a Mac.
A secondary issue common to every storage system that uses smb:// is that there are restrictions to the filenaming conventions, and restrictions to the max. size of files.