I have also had a ReadyNAS (NV+) for some time and have been extremely satisfied with it. The device does not come cheap, and it isn't silent, but it is very c

I have also had a ReadyNAS (NV+) for some time and have been extremely satisfied with it. The device does not come cheap, and it isn't silent, but it is very capable, offers decent performance, and lets you access your data in a wide variety of ways (NFS, Rsync, AFP, CIFS, etc). It is relatively open as well, including allowing full root SSH login, and has various software add-ons as well. Until an equivalent OEM product comes along that supports something like ZFS, the ReadyNAS is probably one of the best options available.