"The smallest distribution that I've used so far is Geexbox at
8MB. But, it can't be considered as a complete 'desktop' distro
since it only specializes in playing multimedia files.
"So what about SliTaz? As described in Distrowatch, SliTaz
GNU/Linux is a mini distribution and live CD designed to run
speedily on hardware with 128 MB of RAM. SliTaz uses BusyBox, a
recent Linux kernel and GNU software..."