Well the Markets is one place to get these. The problem in buying stuff there is that if there's a problem with the kit you either have to wait a month to see the vendor again (and most are pretty accommodating) or go to the next venue where the markets are on and see them there (receipts are essential).

I bought two IDE drives because they plug into the set top box to make it a PVR (and I wanted to swap the old one old so I could extract a couple of films on it) and the media PC has a motherboard that wants to boot from one. But SATA drives were there as well.