My SATA hard drive (primary) had started to behave erratically over the past few days. After lot of troubleshooting, I was forced to reinstall windows on my backup drive(IDE), but for some reason, it wasn't able to access my SATA drive and would hang all the time. I finally had to unplug it for Windows to become stable again. My last backup was a couple of weeks ago, so I had a few important files stuck on the SATA drive. Hence, I had a pressing need to get this kind of gadget.
I got the unit, a brand called R-Driver. It comprises of a power adapter, SATA/IDE power plugs and cables to hook up to SATA/IDE drives. It worked pretty well, gave me a sustained transfer speed of around 20 MB/s while transferring around 10 Gigs of data. The cost was 450.
A really important lesson I learnt was to have a seamless and up-to-date backup mechanism. One of the solutions that I am exploring is using Microsoft Live Sync to keep the important files in sync between my desktop and laptop. I will post my experience after I have used it for a few days.