Installation :: Best Distro For Low Maint Samba Server?

I'm doing voluntary charity IT support whilst out of work to keep my hand in. Tomorrow I go on site here and will be retiring an old PIII from desktop service and am proposing to them they turn it into a sambas server. They'll likely let me take it home to reconfigure.

They are running all windoze workgroups with a mixture of XP home, XP pro, and VISTA (not sure what edition). I'd like your advice on the distro and any considerations for Samba install on top of that.

Asides from making it easy for me the other requirement will be that this is fairly idiot proof ongoing to administer. I'm ideally just setting this up and they may in future need some network change - is there a distro that lends itself to that sort of thing more than another? I don't want them to feel they've been left with something only I could look after - obviously it needs to sort itself out with a simple power up etc in case the cleaner unplugs it.

I've used a samba server once before - it should play nice with all the windows stuff, no? ATM they're just sharing a drive on the VISTA machine, so it's not like we need to deal with an Exchange setup - that is what I am trying to save them from! Networking wise - they have one router with four ports and one four way switch. There are only four machines networked now, but I amgoing to add one, plus the server.

One guy there is semi-IT literate, but mainly M$. My primary concerns are that I can configure it to work myself without too much hassle and then I can hand it over and they can run with it.