Can I also suggest avoiding any hard-drive with any words that appear like 'deskstar'.  I've had three IBM Deskstar drives die (out of four) and so I would simply suggest avoiding them at all costs.  Best bang and reliability for the buck seems to be the Seagate Barraccuda drives (5 year warranty, fast, reliable, quiet, not too dear).  I'd also recommend the LaCie external drives if you don't want to build an external drive/enclosure yourself.  I've a 320Gb LaCie Big Disk D2 (non USB - a FW800 drive) which is very nice indeed.