Another alternative DLink DNS-323
I have the Dlink DNS-323 for home use which is a step up from the Netgear, but not as expensive as the more professionally orientated ReadyNAS.
I would use the Dlink in my professional environment (I manage a software development team) although it is clearly physically designed to be a desktop rather than server room product.
Here are some relevant links:
http://www.dlink.com/products/?pid=509
http://www.smallnetbuilder.com/content/view/29671/75/
The bundled backup software would be my only gripe, but as you can very easily map a network drive to the device, any solution (Acronis / Windows backup etc) will work.
Martin