Everyone on here has been great helping me as I'm a little clueless about some of this. I just ordered the iMac (4GB 3.06) with a 750GB Hard Drive. I'm looking at a 1TB external harddrive for back up purposes only. (Time Machine) I was thinking about just buying the Western Digital 1TB My Book Home Edition (FireWire 400, USB 2.0, and eSATA) - Costco by my house has it for $229. http://www.costco.com/Browse/Product.aspx?Prodid=11240846&whse=BC&topnav=&browse=&lang=en-US&s=1 But, I've been told in other threads that I should go with an internal and an enclosure. I looked into this and it is slighltly more expensive than the "My Book" mentioned above, but I could get a 5 year warranty over the "My Book" 3 year. My main question is, Is there any reason why I shouldn't just go with the 'My Book"? If I was going to go Internal + shell, I was told I would still want to go Firewire. So, I was looking at this: http://www.newegg.com/Product/Product.aspx?Item=N82E16817198004 What internal would you suggest? What's the difference between OEM & Retail and which do I want? Thanks again for the help - you guys are great.