External Drives

If your going that small, I would say get one that is powered off the usb plug and does not need an external DC plug. Becomes less portable with that plug to lug around. source

Is it possible they're both trying to use the same drive letter? I've had that happen to me before, and I had to reassign one before both could be seen. source

If you're looking for a good hard drive manufacturer suggestion, both Toshiba and Hitachi both produce pretty high quality drives. If you're looking for a name brand, Seagate was still producing some worth-while stuff. I used to rely on WD until they began using reconditioned hard drives in their external lines and screwing customers on warranties. I don't know if it's still an issue, but I still tend to steer clear of the company when making external storage purchases. source

External and Internal use the same hardware, so reliability is pretty much the same. External has the advantage that you disconnect or power it down when not copying files, so if the Mobo burns up, it can't take the drive with it - which can happen with an internal. source

External and Internal use the same hardware, so reliability is pretty much the same. External has the advantage that you disconnect or power it down when not copying files, so if the Mobo burns up, it can't take the drive with it - which can happen with an internal. source