For a more minimal system, one might want to check out SliTaz: http://slitaz.org/en http://slitaz.org/en Under 30mb (compressed, in RAM — just over 100mb uncom

For a more minimal system, one might want to check out SliTaz: http://slitaz.org/en http://slitaz.org/en Under 30mb (compressed, in RAM — just over 100mb uncompressed), and quite fast. No Ubuntu distribution, but packages available for it should be at least adequate for most users.