Skip the LiveCDs and go directly to Debian. You can run either Debian Stable (Woody, old but very stable versions of programs) or Debian Testing (Sarge, slim chance but possibly unstable programs. Debian developers are finalizing Testing to be the next stable release in the near future).
Debian stable - http://linuxiso.org/distro.php?distro=4
Debian testing - http://cdimage.debian.org/pub/cdimag.../i386/current/sarge-i386-netinst.iso 10-Feb-2005 23:51 109MB
I installed Debian tesing via sarge-i386-netinst.iso this past Tuesday. The minimal install is about 200-300MB and includes only the basic shell, etc, filesystem programs, apt and dpkg programs so that you can get updates and install more packages. Debian is great because with a properly configured system I can install apache mysql and php via:
aptitude install apache2 mysql-server php4 php4-mysql

I hope this helps.
James