I just bought the WD "My Book" 500gig, it is quiet and was cheap at Costco. I could have bought 3 for the price of the 1 TB units. It has some nice features like an external light show as it works and a lighted 'gauge' to let you know when it is getting full. You can use either USB or Firewire which is a nice feature when working on older USB 1.0 units, as I had to do recently. The firewire ability really sped things up.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70