If you're planning to do a backup of files (MP3, videos, etc.), then CD-R/CD-RW is definitely your best option. The media is very cheap, and the drives (if you don't have one already) are also pretty cheap. It can store about 6 or 7 times more than a Zip disk and costs a lot less. If you're planning to do a system back-up, backing up to a CD-R can also work. You can also do it over a CAT5 ethernet network because it will allow you to transfer at 100Mbps, as opposed to the 11Mbps of wireless. I'm pretty sure Norton Ghost will let you back up to multiple CD-Rs, but I'm not sure about Windows backup. Hope this helps.