Retrospect is what we use at work on our network, but for a personal computer simply draging (copying) your users home folder onto a CD/DVD manually is fine. If you want something more advanced check
www.macupdate.com for backup utilites that provide automated syncing features.
Another option (and what I personally use at home) is a external Firewire drive for backups. Since most Mac models can boot off Firewire devices you can clone your entire drive this way. Then you'll have a complete, useable system with everything intact and ready to go instantly.
Since the user home folder contains all your documents, photos, music and necessary settings/perferences its the only thing you really need to backup. If something should go wrong with your hard drive use your orginial system disk to do a restore and that will get the OS and Apple apps back (iTunes, iPhoto, ect), install any third party apps/drivers, then copy your users home back and you'll be back in business.