Freecom = not expandable. Only one drive in unit.
[url=http://www.overclockers.co.uk/showproduct.php?prodid=HD-014-BF]Buffalo] is the same really, only expandable by USB drive.
Icybox takes PATA drives
at FAT32
So really it will depend if you think your storage needs will change in future. If you may need more then why not throw a basic base unit together as a server box?