For simple Linux setup on an old PC you can't go far wrong with something like DSL ( Damn Small Linux )
I run it on an old laptop with only 59mb of memory. It's a live web server with some test pages on.
Has a nice simple gui, firefox, xmms(mediaplayer)
I also have Suse 10.1 on a machine, very nice gui features, the sort of things Vista has but without the stupid hardware requirements. ( ie will do transparent windows without any fancy gfx cards, with actually do it using virtualPC or VMWare emulated video cards!)
A link to my kites page on my DSL laptop, apache2.