After my mom's Intel iMac hard drive got corrupted, I ended up buying DiskWarrior 4 to recover the directory since Tech Tool Pro couldn't do it (So now I own both) and it boggles me how good DiskWarrior is. Anyways, disk was recovered and data was backed up and system was reinstalled.

Thank god they made it available for download with an immediate serial number so I could get the drive recovered right away. I wasn't thrilled with the fact that they sent me a burned DVD though, and with only Mac OS 10.4 (and not 10.5 or any other thing) so it was not really worth even getting the disk.

So two things you ABSOLUTELY need for OS X/OS 9 disk and hardware maintnance, is TechTool Pro (or Lite at minimum) and DiskWarrior. Those are a MUST.