The Thing to do is go with the combo cases, and roll your own. With the Firewire option you can avoid issues when burning stuff through a USB Burner from a USB Drive, or when tranferring info from one drive to another. Not having to Cross the usb buss twice. Coming and Going. But Cross through USB to 1394 (firewire is trademarked by apple). So pulling things off 1394 to USB is quicker as well, pull from a 1394 enabled camera or DV device and go into USB Drive. Also added benefit, is say you go to a friends home, and want to move something LARGE, and he only has USB 2.0.. No Firewire..you're SOL, with a single architecture, but handy dandy good to go with a dual case. I have several external devices and all but 2 are dual ( they would have been dual but they were my first devices and I had to learn...)