SliTaz is currently the de facto standard for a lightweight distro, replacing damn small linux. The main reasons are that: its simply up to date; DSL used the 2.4 kernel instead of 2.6, it has a beautiful out of the box interface, it somehow squeezes an insane amount of useful software into a significantly smaller package (30 Megabytes!), and its extremely versatile. It’s breathed life into ancient pentium machines with less than 256 Mb RAM, and what’s more, it made them just as fast and responsive as my current computers! I would not recommend any other distribution for retrofitting an ancient computer, and I can only imagine how wicked fast it must be on a current one.