I have a draw full of old HD's ranging from 4-80GB. All from old PC and repairs over the last few years. I was thinking of getting a caddy so I could plug them in to check what was on them, but found an even better bit of kit. It's simply a USB cable with an adapter on the end that plugs in to SATA, 2.5 IDE or 3.5 IDE drives, plus a power supply. So I can plug the two cables in to the bare drive, plug in to the USB on the PC - Linux auto mounts, and hey presto, I can get all the old data off, and shred as necessary.
A very well spent £10, from Ebuyer IIRC.