This may be overkill and is the only part of the system that you don’t really need to put into place, but if you like the idea of having your backups stored locally (which has the convenience of being able to restore them easily) then you’ll like this idea.
Basically, setup the email backup system described previously but use a desktop mail program such as Mail.app for Mac or Outlook for Windows to download the emails to your computer. *BAM* all your backups are now on your system.
If you’re a Mac user buying a Time Capsule will allow you to backup your local computer (including all the website backups) and because it’s wireless you can just shove it in a cupboard, out of sight and never think about it again. That’s some extreme blog backing up right there. Tad overkill, but the Time Capsule is a very nice device.