Time machine is pretty cool for backup software. If you are not familiar with it, you can find out more about it here. After I installed Leopard I went out and got a 750 Gb external drive from Costco so that Timber and I could use Time Machine to do regular backups on our machines. I haven't had to restore anything yet, but I can rest assured that everything is backed up incrementally and automatically as long as my dedicated external hard drive is connected.