Just go buy a secondary, internal or external, hard drive for back up and use CD or DVDs for long term archival of documents, photos, and other info. Haz, your gonna get bit in the ass by those flashdrives. They're great for file transfer, replaced floppies, Zip, and Jazz well enough, but don't expect them to be a secure and reliable back up. Online back up is OK for a business or studio, but I'd wouldn't recommend it for home use, but it works fine, with some downsides.
My current rig is running six HDD:
One 500 Gb - primary OS system drive, programs and all games are stored on this one
Two 320 Gb - two 320 Gb drives setup in RAID 1, which sets up multiple HDD to mirror each other, so that information in on at least two separate physical HDD, if one crashes then I'm up and running in ten minutes with zero data loss, this where I save all my data using a vast, but simple, file system
One 160 Gb external - USB 3.5" used as another back up to the RAID array, in case of computer failure I can relocate it easily to another machine and pull needed files
One 500 Gb NAS - network attached storage that is connected to a server machine, anyone on the network can use this drive as backup or as a means of transfer between machines on the local area network
One 160 Gb external - 2.5" mobile drive used to back up data, then gets thrown into a fire safe
Remember for nonreplaceable file, such as photos, use CDs or DVDs, because they're nonmechanical and won't fail or age like magnetic or electric storage such as HDD or flashdrives, then put them in a fire safe.
EDIT: Forget everything I just said. Go buy a tape robot!!!
