The Drobo is a pretty renowned little NAS, making it easy to add networked storage to your home/office. The new DroboPro is a bigger, meaner NAS that's equally simple to use.
The DroboPro, announced today for a barebones price of $US1300, connects to your network via iSCSI (ethernet), Firewire 800 or USB 2 and supports up to 8 3.5-inch SATA drives for a maximum of 16TB of storage (a number that will obviously grow as drive capacities do). It's optionally rack mountable, and the whole system takes up only about a square foot of space that's but 12cm tall.
It's Vista/OS X compatible, and I almost wish that my tiny text files took up more space so that I could justify owning such a ridiculous amount of storage. [Drobo]