As a battle-hardened sysadmin, I've seen a lot of broken systems (some I broke, and some were broken for me). I've carried a number of rescue disks, including tomsrtbt and the LinuxCare Bootable Business Card, but over the past year or two, I've started to rely completely on Knoppix as an all-in-one rescue disk. Below are some real-life accounts of how I've saved some broken systems with just my Knoppix CD.
Looks like I need to go pick up a copy of Knoppix Hacks for myself. I haven't played with Knoppix recently, but I did used it to get data off NTFS formatted hard-drive by booting up Knoppix and running the included ssh daemon. Very slick.