The Seagate FreeAgent Desk is the desk-sized version of Seagate's external drives, and while it's technically been replaced by the Backup Plus line of desktop drives, but it's still widely available, and comes in capacities ranging from 1TB to 4TB. The FreeAgent line are almost iconic, and as the name implies, they're desktop drives, designed not to be moved terribly often. The FreeAgent line comes with USB 2.0 by default (although the newer Backup Plus supports 3.0), and Seagate's built-in automatic backup and encryption software to keep your files and data safe.
On the up-side, even though the FreeAgent series is fading away, they're still available, ranging from around $37 for 500GB up to $60 for 1TB to $150 for 1.5TB at Amazon. Alternatively, the Backup Plus line is a natural upgrade for more modern devices, sporting USB 3.0 connectivity that's upgradable to Firewire or Thunderbolt if you need it, visual storage and health indicators on the front, support for cloud syncing and auto-downloading photos and media from social networks, and more. They're available in capacities from 1TB up to 4TB, starting at $82 for 1TB, $92 for 2TB, $118 for 3TB, and $150 for 4TB at Amazon. If you're interested in an older FreeAgent, there's no reason not to look at the newer models instead.