When Leopard was released, I wanted to transition from my current backup solution which was SuperDuper to a network based external hard drive to Apple’s Time Machine.  Before switching completely to Macs I had always put together my own hardware from buying parts and putting a PC together to buying external hard drive enclosures and sticking my own hard drives in them.  This isn’t a bad way to do things.  You definitely get more for you money.  The main reason for my transition is I wanted support.  If something failed I wanted to just send the entire thing in and not have to worry about it.  So this is one example of that.  I went with Western Digital drives because they were relatively inexpensive and they look nice next to my Macs.