For many years I've been backing up my various computers to external USB drives. Since becoming a Mac convert I've switched from rsync to Time Machine and never looked back.
jwz's most excellent backups article is what really gave me a kick in the pants to back up all the time. And having a backup has saved my bacon on more than one occasion.
The only thing missing from this equation was my "house burned down" backup.
That third drive? Do a backup onto it the same way, then take that to your office and lock it in a desk. Every few months, bring it home, do a backup, and immediately take it away again. This is your "my house burned down" backup.
Yeah that. That I have never had. So I've decided to fix it.
Now I backup everything online to Backblaze. For $5 a month, it's a no brainer really. So far it's never gotten in my way, has backed up everything and restored what I needed it to in testing.
Even though everything is encrypted, I did have a brief moment of "oh noes, all my stuffs are on teh internets". So I added my own encryption key into the mix as well.
I have two backup external HDs at home but they stay there and in not the best at constantly backing up but that's mostly because we rarely use desktop computers anymore and, when we do, the work that's done isn't worthy of backing up. Our iPhones and iPads do most of the work and those back up to iCloud, Dropbox, Flickr, and Skydrive. I do need to do more of a proper backup on our iPads (iPhones get synced far more regularly). And unwound like to do the "house burned down" portable HD backup but need to buy one. The two at home are a huge MyBook HD and a Time Capsule that doubles as our wifi router so I can't move that.
Yeah, I would never go back to using an actual desktop computer again. Laptop all the way since 2008 ;-)
A friend and I have external drives at each other's houses that we do nightly rsyncs to from our local backup drives. I don't do this for my Time Machine backups, but I have my home directory backed up separately as well as Time Machine and that does get included.
Heh, that's a cool idea that you rsync your home directories to each others houses. You've got the "my house burned down" backup covered there then.
This last year, I bought multiple Seagate 1gb external USB portable drives (the kind that are self-powered by the USB port) and dedicated each one to each of the 3 Macs I backup (mine, my wife's and my daughter's). I keep my daughter's at my house and take it to her place a couple times a month to do backups. Not so much as a "house burned down" but more as a "house getting robbed" since she lives in an area that could experience a break in more often.
As for my external drive, I have a powered ext USB drive that does my Time Machine backups, but I also have a 320gb ext USB self-powered that I do a Carbon Copy Clone to a couple times a month. Usually done before I update to a new OS X version, but also I keep it at my office for the "fire" and "robbed" scenarios.
Having something offsite is the key and I think you're covered here sir.
I am super-paranoid about my files. Everything is backed up locally, to BackBlaze, and on a portable drive in my work safe. Photos are on two redundant RAID drives and a third portable drive in my work safe. If I lose everything, hey, I did what I could!
Haha, yeah if you manage to lose something after all the work you've put in then you certainly can't blame yourself ;-)