There is a lot to be said for Mandriva. It has very comprehensive set of configuration guis - most ALUG people do not need them, but its nice for the rest of us. It will install all the desktop environments you will ever want with no strain. Its easier to install new stuff than Suse because you do not seem to get caught in the endless circle of dependencies as much. It is quite stable. There are lots of rpms for it. I prefer it to Suse, which I have installed with a couple of people, and have had some irritations with.
The only real criticism is that moving from version to version is a bit problematic, and you have to agree with what most informed people say, that it is a bit ridiculous to have to do a clean install for every major upgrade. But this applies to everything except Debian or maybe also Gentoo. I think Suse is a bit better, it has a sort of cleanup tool, which seems to work.
if you want Debian based, and you want simple and ordinary user friendly, its worth looking at PCLinux and Mepis. Both use apt for packaging. Both come on one CD. PCL has all the Mandriva admin stuff. Worth a serious look. Both are only KDE, but you can add Gnome easily enough.
The one I really like is elive. That is a work of art. From the country that brought you the Trappist Triple, and the paintings of Breughel, and you know it as soon as it starts up....
If you want fairly stripped down and reasonably fast for an old machine, Vector and Vector Soho are not bad.
If you want super stripped down and very fast for a very old machine, DSL.
But if you want to laugh aloud, elive.
Peter