It lacks RAID, but I'd recommend a 1TB Apple Time Capsule. It's a wireless router with on-board storage - there's a USB 2.0 port to add more - and printer sharing. I have the 512GB version, which I use as a media store and file-swap facility for a couple of Macs, my partner's Vaio and my kid's netbook - my own netbook too.
Works a treat and is reasonably priced. And you can access its content remotely over the internet.
More here: http://www.apple.com/timecapsule/