I had a couple of Buffalo Terrastations at my last company, we needed a relatively fault tolerant device for storage of stuff that was somewhat important, but not important enough to backup to our already taxed tape backups.
Buffalo Technology - Products - Network Storage
Worked pretty well for what they were, Gig-E connection with native (although somewhat clunky to configure) active directory support. They were not as fast as I would have liked, but not too bad, and for the role they worked fine.
Tom