A blogger at TheLinuxNewbie have tested 11 LiveCD's – amongst those are Damn Small Linux, Knoppix and four flavours of Ubuntu. Mandriva One 2006 came out as the winner.
Read the review here
However, as I have skipped around web, I have discovered numerous choices beyond Ubuntu that are top quality Linux distributions.
Here is a list of pros and cons, as I see it, from 11 of the more popular Linux distros. (No, this list is not exhaustive, nor shall it ever be. I hear that every 7 seconds, there is a new Linux distro created somewhere in the world!)