People ask me all the time about using linux to recover lost files on a crashed machine. My usual response is to tell them to learn linux now so that when your machine crashes you will no what to do. For some of the less disasterous crashes lifehacker.com has an article about recovering lost files using knoppix. It's a pretty decent article with lots of screen shots.

The other important thing is that the latest version of Knoppix V 5.0 is out as of  June 2 2006.

Not only is Knoppix the best bootable CD/DVD version of linux it is also great for running under vmware and qemu.