Single CD distros that I've used or downloaded include:
SOP Linux (maybe SOT, might have written that down wrong
Mandrake (all versions)
Debian (I think you only need the first one)
Older SuSE distros, actually probably most "older" distros would only have 1 disc, just depends on how old you go
Ok, so some of those might have more than 1 disc, but you would only need the first to get it installed, the other disc(s) are just extras. You can also look into floppy distros if that is your cup of tea.