SO many choices but backup is all about convenience to make it happen on the frequyence it needs to occur

Buy a Maxtor
The shared Storage plus is my favorite
Shared Storage Plus
Or the One Touch

One Touch
Either way set it to back up the directories wiht all yrou data (include all the ones buried deep in the Windowz tree

I use Karen's Replicator (free)
Replicator and have it back up daily any time I am connected ie not travelling. WOrst case I loose from that point. More important stuff gets posted to a USB key while travellign or uploaded or even e-mailed to myself via gmail for extra resislince.
Favorites used to be ab ig dela but mostly google search has repalced my 700 off favorites that I keep