Just like every machine with moving parts, the hard drive that holds your iTunes library will eventually stop working. Read that line again - I didn't say might stop working, but will stop. It's going to happen, so be prepared.
Mark Nichols at zanshin recently wrote about his own experience of swapping and burning CDs and DVDs to back up iTunes purchases (something we blogged about awhile ago). That got me thinking about strategies for iTunes backups.
Time Machine and SuperDuper make it easy to execute local backups at regular intervals, but that's only half the battle. A good off-site backup of your mission-critical files (and I don't know about you, but for me, music is definitely considered mission-critical) is essential. You can go with services like Mozy or CrashPlan.
Personally, I've been very happy with Bandwagon. For only $12US per month, they provide the means to backup to either Amazon S3 or your own FTP server.
So, what's your solution? Please share in the comments, and save Mark another day of swapping discs in and out of his optical drive.