How do you back up your data?

You are an intelligent, tech-savy group: what is your preferred method for backing up your data?

Recently, lightning struck my house and fried my external hard drive. I was using it to store my music and pictures, and to backup my laptop's hard drive. I can recover the music from my ipod and the laptop's hard drive is fine, but I lost my pictures.

So, moving forward... it seems like I will need two external hard drives: one for active storage, one to backup the other and my laptop.

The problem I see, though, is that if the backup HD is connected (RAID 1? Time Machine?), it will be vulnerable to most of the same threats as the primary HD (fire, lightning, theft...). It would only be protecting against hard drive failure.

Anyone have a better method?

Also, I'd rather not have another monthly bill for online storage

What about the good old cd/dvd?

I use a combination of dropbox, Google drive, and a cheap VPS server for backups. It's convenient and far more reliable than local backups.

I have two external backup drives, and I store one of them at a friend's house. In the past I have stored the second backup drive at my workplace.

a) backup onto a laptop powered off a surge-suppressor and connected to the network via a hub also on the surge suppressor. (IME UPSs caused more downtime than they saved, so I no longer bother with them.)
b) disconnect your external backup drive when you're not actually making backups.

@Valette: Thanks for the suggestion, but I don't trust CDs' shelf-lives. Most most things I've read say you shouldn't rely on them to last more than 5 years or so. Also, I have a lot of pictures; would be a hassle to record and store that many CDs.

@z: the free versions of online storage don't give you enough room and I don't want to pay for the pro versions.

@Ignatius and Phil: This is the route I am leaning towards. Leaving one external HD connected to my network to store my music and photos and periodically connecting the second HD to back everything up (any particular reason why you use a second laptop instead of a hard drive, Phil?). It's not automatic so I will have to remember to occasionally update the backup, but better than losing the whole RAID when lightning strikes again.

The two reason I mentioned a laptop as the device onto which to take the backup are that:
(a) it's small, and can be tucked away in a cupboard or wardrobe easily. One of these small headless units would do an even better job. You never really need physical access to the device; and
(b) the last time I saw a laptop destroyed via the electricity supply (should the surge suppressor not prevent that), the hard disk remained unharmed. The last time I saw a workstation destroyed via the electricity supply, the hard disk was fried. I viewed the laptop as an electrical crumple zone. However, sample sizes of 1 are not statistically valid.

I back up source files (which is all I really care about at work) on servers at work to my work PC, then back up those to a rotating set of three flash drives. This is in addition to whatever the sysadmins are doing to back up the servers. (The one time I needed to go back to a source file more than 6 months out of date, I found their backups went back at most 3 months. And that source was never in a source management system until I took over the project.) The flash drive's data is compressed using bzip2 and encrypted using a public key whose private key's password I hope I would be able to find in the event of a restore.

I used Mozy for a while, then iDrive. Mozy was unreliable, sometimes not performing what should have been a nightly backup for a week or more. iDrive was just too intrusive. I mean, I tell it to back up the contents of exactly one directory once a day at 3 AM, so what the heck is its Windows service doing using 100% of 1 CPU for 10-30 seconds at a time during the day? I'm still looking at online backup services, most recently at tarsnap.

To back up my home computer, I use Time Machine, supplemented with a secure online connection to synchronize backups of a small set of source files (most currently, my Keccak implementation) to my work PC.

At one time I was backing up many files of my parents' rig using a secured TCP connection to my home computer, but when they upgraded past OS X 10.4, I got them an external drive to use with Time Machine.

Wikipedia has a giant table of online backup services.

You don't believe in proof by example? :)

The xxcopy utility, run from a custom batch file, backs everything on my hard drive for me, onto a 1TB portable hard drive.

I keep the hard drive stored away from the rest of the house, in a garage that is 30 yards or so away.

That's it. Nothing fancy.

Aren't CDs and DVDs a dying breed already?

I do not care. At the office it is not my task. At home, there are no relevant data. Really, I think there is no need to do backup data, just throw it away!

Google Drive + Dropbox + Bitcasa provide enough storage for most valuable data.

With a good camera and little kids running around, I could fill 7 GB (Google Drive + Dropbox) in no time at all. (That sounds creepy)

And as I said before, I'm not going to rent storage online when I can buy it for, what, five cents a GB these days?

extern harddisk and store it at your friend's place. If he is a tech dude you might even be able to hook up to it online from home.

I carry with me a 500 Gb external hard disk. And it gets cloned dayly and automatically both at work and at home using Carbon copy cloner on mac os. I do this since I lost some data due to my hd being stolen. With this system I have a "cloud" in my pocket that doesn't depend on google or another company, it even work without an Internet connexion :)