Which are the best USB hard drives reviews?

I know you said that you want it to be USB hard drive, but I would definitely consider a desktop backup drive it’s a lot better than USB hard drive. I really like the WD My Book Studio that I use for backups/external storage. They come from 1-3TB so it should be plenty for backups for you and they're FW800 so it's all pretty fast. If you're worried about them getting knocked around then just unplug and hide the drive when you're not backing up. After the initial backup, the incremental backups generally only take a couple minutes at most. If you really can't live with a desktop solution, then there is the WD My Passport Studio. Those only come up to 640GB though. I personally prefer FW to USB, so I would stick with those. Also, USB 3.0 won't do you any good since you have USB 2.0 ports on your MBP.