I was listening to the Security Now podcast and there were some interesting pieces of software that were discussed:
SpinRite: This program makes a bootable CD or floppy that can be used for crashed hard drive recovery- even when the disk is not accessible to Windows...
I am not even sure how this works as the drive will simply click and freeze Windows until it is unplugged. The software does a low-level scan and re-scans sectors with errors to recover data one bit at a time.
Diana's Mom had the hard drive in her laptop crash and I had given up on it: I replaced the PCB board with one from an identical drive, I tried several different IDE-to-USB adaptors and I even put the drive in the freezer for a few days in an attempt to recover data. This program ran for about an hour and found several bad sectors- it was able to recover all but one; and that did not appear to be a critical sector as I was now able to recover all of her pictures and documents!
Perfect Disk: a very thorough disk defragment program- this will even defragment system and swap files. It is hard to see a big difference on a 10K rpm Raptor drive, so I cannot say if this is a 'must have' program- but it does look pretty cool!