Choosing a Security LiveCD in 2010
A few years ago security oriented live CDs were a dime a dozen, and it was simple to find one that fit your preferred usage models. A few years later, the rolls of the dead, discontinued, or just plain no longer updated include Auditor, Whax, Fire, Knoppix-STD, Local Area Security Linux, and many others.
Along the way, Helix, which a large number of people used went commercial, although at a quite reasonable price.
Now, if you want a good security distribution, your choices are a lot narrower. My default is BackTrack, which is used widely by groups including SANS.
More specialized tools like Ophcrack (a Windows password cracker) remain available, and can help fill out a security toolkit, but the days of huge numbers of distros appears to be over. Most of those that remain can be found linked by securitydistro.com.