Looking for an external drive for an iMac late 2006 to hold an ever expanding iTunes library. Question is good old cheap USB 2 such as this Seagate 2tb or expensive but rather lovely WD Studio 2tb? This drive will be used by the iMac to stream to 2 ATV3's but rarely at the same time. I believe that data transfer on Firewire is quicker and more sustained but is that necessary here? Thanks in advance.