I was going to be good and avoid mentioning any specific Live CD, but, since others are making endorsements... ;-) Ubuntu seems to be up- and-coming. Worth at least looking at their Live CD's (available for x86, PowerPC and i64 architectures).
Regards, - Robert http://www.cwelug.org/downloads Help others get OpenSource software. Distribute FLOSS for Windows, Linux, *BSD, and MacOS X with BitTorrent