HDD. The GoFlex Desk line is about as sleek as it gets for a non-mobile drive, with 1/2/3/4TB options being made available. The stock model ships with USB 2.0 / 3.0 support, a required AC power adapter (blah) and support for OS X and Windows platforms. The entire unit weighs but 2.38 pounds and checks in at 6.22- x 4.88- x 1.73-inches; true to the GoFlex name, the lower base can actually be swapped out for those who'd prefer a different interface (you know, like FireWire or Thunderbolt), and there's a four-LED capacity gauge on there as well. In our limited testing, we consistently saw USB 3.0 burst rates top 100MB/sec, while sustained transfers hovered closer to 60MB/sec. When used on a USB 2.0 rig, we saw reads and writes hover between 30MB/sec and 40MB/sec. As for pricing and availability? The 4TB flagship can be found right now at Seagate's site for $249.99, while the GoFlex Desk for Mac -- which touts both Firewire 800 and USB 2.0 -- will be available in Apple stores by the end of the month. We're told that Thunderbolt will be supported once that GoFlex adapter is let loose, but an ETA isn't quite ready for public eyes.