Cheap NAS recommendations

I’m looking at the D-Link DNS-323 right now, but before I pull the trigger was wondering if others had some recommendations for a NAS that provides OS X compatibility and mirrored RAID support. Other than that, don’t really need anything fancy like music serving, etc. Just something simple, network accessible, cheap, and redundant.

I saw a Linksys unit but the reviews said its performance was so bad as to be nearly worthless. The D-Link is also interesting because it can be hacked fairly trivially with fun_plug.