I've also enjoyed working with Slackware even though it seems to be much harder to use.
thats not really true; not really harder, you will see if you use Slackwre, it is actually easier to use than most...
it doesn't get in your way or do things behind the scenes as buntu's do...
you can try Slackware-derivatives as LiveUSB
SalixOS is Slackware Based XFCE4
Fathom's Slax remix is Slackware Current and runs like Slax KDE
and my own nFluxOS SC current Fluxbox
all those have persistent usb, etc, and they'll all 3 fit on your usb too!