Unless you are forced to rely on it as your main PC, you may be tempted to throw an older computer away, thinking it is useless and obsolete. But don't make that mistake!
Over on Daily Cup of Tech is a great article about twelve useful things you can do with an older PC, that you may be thinking of permanently retiring. All kinds of things from a firewall/router to a file server to a bittorrent box.
So head on over and get some ideas and don't put the snail on the curb just yet. It still has plenty of life left in it.