I have an old Mac Mini (Core 2 Duo, 1G ram) and recently put Mint Linux on it with Mate as the desktop. This is a desktop designed for low power machines and I was pretty impressed with how well it worked. Basically it could run a browser (Firefox), email (Thunderbird), word processor (Libreoffice) and music player (Banshee) with no problem and memory use stayed will within the 1G limit. The Mate UI is pretty plain but works ok.
Obviously we are mac fans here but since this machine can't run up to date software it seems like a good way to keep it useful. Especially if I was using this to give a computer to a non-computer savvy relative I think it would great, especially since it would auto-update all the software. I'm not sure about how well all that software would run at once in snow leopard but I thought this computer was pretty slow before.
What do you guys think? Any upside to using Snow Leopard in this kind of context? Normally, I'd promote Macs for non-computer savvy relatives but that would mostly be for iPhoto etc. I don't think linux is good for that kind of stuff but a lot of people only need a browser and email.