Basically Knoppix is a bootable linux distro that would work fine as a nice desktop. Knoppix-STD is a hacked version of Knoppix that is chuck full of network testing/analyzing/hacking tools. There isn't that much in STD that isn't in Knoppix, the author just more or less cleared out the regular menu and put everything right there, however the menu is ogranized like ****. I would go with the regular Knoppix, you just can't beat it and it has most all of the tools you would need anyways.