The only thing that puts me off these big drives is if something goes wrong. I'd rather have four 500GB external drives than one 2TB drive. At least then if one goes down it doesn't take all the info with it, if you see what I mean.
You don't seem to be getting much in the way of practical suggestions of a make or model. The latest Western Digital USB 3.0 2TB will be here soon if you can wait a bit click here Fast but expensive and you'll need the USB 3.0 upgrade card I presume - For A Few Dollars More!