Guess we'll have to half disagree on this one.
ANYTHING that makes making a backup more difficult or time consuming lowers the chance that it will be done regularly. That's the main reason that I'm not big on encrypting backups. The best data security is to not let your data out of your sight. With thumb drives the size of a car key today, there's no reason not to put one on your keyring and make your off-site backup.
THAT BEING SAID - your ON-SITE backups you can AUTOMATE - as again, the more the user has to do, the less chance that they'll actually do it. I learned this from long, hard experience doing disaster recovery for my clients who were just too busy to put a tape in the drive and double-click on the desktop icon at the end of the day. If the stupid thing wakes up at midnight, copies the database, and goes back to sleep, then the backup is done, and no worries. There are a BUNCH of services out there now, all cheaper BTW than AC's offsite backup service (Jon? you listening??) Hell, Carbonite even has radio ads now for their backup service (although I don't think THEY'RE cheaper).
The best backup for an internet connected network would be a thumb drive to take home (in case something fails) AND an automated off-site or on-site backup.
Make sense?
Regards,
V.