Ok Everyone,

Finally installed the new computers and have played with distro's. This is the conclusion for those that are interested.

Firstly, the two new computers are both running amd 1.3ghz processors with 512mb of ram.

i started out with Mandriva 2006 free edition, loaded first time, added to network first time. All seemed good, but the kids just didn't like it all that much.
Next I tried 'Breezy Badger', which performed much faster, easy load and networked first time. Kids liked this system and seem to prefer Gnome to KDE. We had trouble getting flash to work.
After this we tried PCLinuxOS, just could not get it to install correctly, so we gave up snd moved on to Debian Pure, which did not see the wireless network card.

In conclusion the kids have voted to keep the 'Breezy Badger' and I now think I have solved the flash issue by opening up the repo's to include multiuniverse.

So, I would like to thank all who helped with their contributions and hope this may of been useful in some way

I still have a Slackware-current desktop running on a very similar system. 800mHz, 256m ram, 64m graphics card etc.
Never had a problem with it, it screams.

If you absolutely want the fastest performance on that machine -- you're looking at using Gentoo and XFCE. However, Gentoo's install is not easy and it forces you to learn many things about Linux. That being said... once it's up and running... it's terrific. Portage and baselayout are the two best things I've ever encountered in any Linux distro.

I started Linux using Mandrake 7.2 ... it was good enough to lick my wounds as I was switching from WindowsME. I followed Mandrake all the way up to Mandrake 9.2 when I got a new computer with XP. All that time nothing completely satisfied me -- Mandrake would always have some problem that was impossible to fix or extremely troublesome. I stuck with it until Mandrake 10.0 ... when I purchased a TV tuner in the hopes of having a MythTV "linux tivo". That was the last straw. From there I went to Fedora where I ran into the same "hard to get everything working" problems, including (most annoyingly) no real standards followed within the file system. Config files placed in all sort of bizarre locations... /sbin not being in the executable PATH... etc. I tried Ubuntu... is was nearly as bad as WindowsME for me ... just completely vomited on my hardware, and I hate Gnome.

So I kept on wandering... Kubuntu... Mandriva... Debian (with it's rather angry Freenode users)... and finally Gentoo.

Gentoo's installer kicked my butt... took me a good 2 to 3 days to get it installed. But when I did... the holy grail was sent. I found things worked slightly quicker since things were compiled and optimized for my hardware. I found conventions in where files were put in the filesystem. No more bizarre located config files. I found with portage I would never have to reinstall Linux to update it again.* I found by installing Gentoo I learned alot about Linux. I found that making sure the features I wanted worked was no longer a problem -- with USE flags I could "flip a switch" on a feature I wanted... and it would just work after running
# emerge --newuse world

With Gentoo -- I found the first Linux distro that solved all my needs and layed things out nicely. It had great documentation, and great community on freenode and their forums.

It was the first distro that allowed me to delete my Windows partition... for good.

Just my $0.02 .. hope it helps.

* For those claiming this functionality in apt-get (especially Fedora) -- I've had two Fedora boxes fail to boot after trying to upgrade between Fedora releases using the apt-get functionality.