depends on your budget and skillz with a screwdriver i guess. you can save some serious money getting your own case and stuffing a drive in it. 8 screws, 2 cables, no problem.
if you have money to burn, buy one already put together.
pick usb or firewire based on what ports you will have available. saw the LaCie external already. either will work fine. usb is usually cheaper, but you can find decent deals on cases with both. newegg, ewiz, buy.com, etc... good luck.