Aghh ok..I say for that the best solution is simply purchasing an external hard drive and backing up all your data to it. Or did you want something a little more automated to run on set schedules and such?
Currently this is what I do on my home machine. I have 3X320GB hard drives active on my PC. I have 2X320GB hard drives I use only for backups. I hook them to a enclosure backup the data I deem most important and then put them away for a rainy day. I back up maybe once a month in terms of large data (Movies, Music, etc). I backup all my important important stuff like documents, family pictures and such to a 120GB HD and I also back that up to DVD-R's as a 3rd fail safe. Ive been lazy lately though so I need to do one