Live cd's are great for the experienced hacker and for the neophyte that doesn't have a recourses to install a Linux partition. Speaking of installing these disto's are a peace of cake to install on your hd!
http://www.knoppix-std.org/ (KDE)
Knoppix-STD is really amazing. It has an amazing list of tools all on a LIVE knoppix cd. On there site they don't list the full glory of tools that this strumpet continues, but I assure you it is quite amazing. It is made by a network security teacher and it clams it is for constructive purposes. Well true many tools have duel purposes. For instance Knoppix-std contines John the Ripper if you "forget" your password and it has AirSnort if you don't have access to your AP and you don't have a WEP key.
I Feel there next release it going to be out of this world, it is supposed to contain 60-80 more tools! I am not quite sure how that could be, but hey. All I can think of is a bunch of compiled exploits. I am under the impression that Knoppix-std, Phalk, and LAS are all in competition. So they will cop the others tools trying to beat them.
Here is a screen shot:
http://www.knoppix-std.org/ss_alpha.png
As you can see it not only uses FluxBox(thank god!) But it has OpenMosix!!!!!! This means that you could bump on down to a computer lab and have your very own supper computer complete with very powerful hacking tools!!!!! Truly a daunting prospect!
http://www.phlak.org/
Phlak uses FulxBox which is pretty cool it isn't as big as knoppix-std(600meg) Phlak(450), however on Phlak's site it lists the tools it has so you know what is on the cd. From my day to day use of such tools I find Phlack to be perfect. Use that extra 250 meg for another burn session that has MP3's, drivers, exploits, your favorite backdoor for windows. It is a lot easer than remastering the cd.
http://www.localareasecurity.com/ (FluxBox)
LAS is pretty cool form the standpoint that it is great if you want a fully functional operating system choked full of hacking tools on a Flash Stick or a business sized cd that fits in your wallet. I have a friend that modded the 53 meg version and put it on his Pocket PC. If you are going war driving even this version has what you need. I took the 185 meg version and filled it with mp3's, a few tv shows, some roms and emulators, exploits and various other tools that I needed.
Peace