Last month Knoppix 6.0 was released, and it’s even faster and prettier than earlier versions. But it’s still designed to run well on older and slower computers. Among the changes in version 6.0 is the switch from the KDE desktop environment to the LXDE graphical environment. More here and here
Knoppix 6.0 also boots twice as fast as Knoppix 5, and comes with fewer applications preloaded, which helps keep the size down. While the main disk image weighs in at 645MB, it can be remastered to use 256MB or less.