Seems to be a bit of a renaissance of security-oriented livecd distros floating about. Somewhat exciting since the long-past days of things like Phlak, Knoppix-STD, and some other one that had some green in it, was also an acronym, and included the letter “G” somewhere…I forget.
SecurityOnion has been updated!
For any other ideas, check the livecd menu category to the right. Yes, I’m missing some like Helix or Nullbound. I just don’t always feel right grouping [off-and-on] commercial offerings under the ‘livecd’ category. Others like Russix (wireless-oriented livecd) seem to be MIA.