I am looking to purchase an external drive for an iMac 5K. Thought I would take the plunge into Thunderbolt over USB 3.0. Does anyone have any recommendations for an external Thunderbolt drive? It's going to act as a backup / occasional use drive so I don't require anything fancy such as RAID configurations. A single, high capacity drive will suffice. Prices seem pretty high for what I've seen...would like to keep it south of $300 if possible. If not I may abandon Thunderbolt and go with USB 3.0.