for basic NAS you can spend $99.00 for this BASIC NAS:http://www.datoptic.com/2bay-nas.html
or just us freenas to buil yourself a NAS
BTW it's a awesome NAS OS - Totally agree with extremepcs.
Same here both runs as home and at work
Mine are base on the hardware raid SPM394 from DATOptic
I built for my client a 40TB base on FreeNAS and SPM394http://www.tomshardware.com/forum/265641-32-40tb-server-performance-issue
This server only consumes 180W :-) Talking about green