I bought a Fantom G-Force MegaDisk 1TB External. Cheaper storage you won't find. Failed after about a month and took 500 gigs of data with it. Cracked the case open and found two 500 Gb Seagate drives inside, so it's certainly not awful components. Maybe I just got (un)lucky.
(As an aside, I plugged the drive that didn't fail internally in my PC and managed to recover all my data.)