You can sometimes get lucky on the LaCie site. I got a 500 GB NAS for $299 a while back when they were going for much more. I got a refurb from the outlet section.
I have a bunch of external storage at home and I've found that most brands are fine, even the no names.
Also, you can provide yourself NAS in the future w/ a USB hard drive by buying one of the new Apple Airport Extreme Base Stations. It supports a USB hard drive connection. Then any computer connected to the network can see the drive. Pretty cool. It supports USB hubs so you could just keep adding drives whenever you need them. I have mine next to the router and DSL modem in the closet, so noise isn't a problem cause it's out of sight. Access times are pretty good too. I've archived videos, photos, and many large files w/ no issues. It works w/ the new 802.11n wireless standard and can conceivably go over 130 Mbps, faster then your normal wired connection. Though you need 802.11n on your PC side too.
