Encrypted remote backup with Duplicity
I've been using Duplicity for a while now to backup my Linux (virtual) servers. Duplicity is a bandwidth-efficient tool to do encrypted incremental remote backups via SSH, rsync, webdav and many others, for example Amazon S3.
My experience with the tool has been very good. Unlike a lot of incremental backup systems which work on the file level, duplicity goes a level deeper and only backups the blocks of files that have changed. This results in compact backups even with crazy database systems (like InnoDB for MySQL) which put everything into one big file.
As the backup can run automatically from the crontab daily (or even more frequent if desired), it is an excellent no-hassle solution to have an extra level of safety for your files.
Amazon EC2 storage is pretty expensive, and if you only need secondary off-site backup, you can just as well use some cheap online backup hosting box such as Data Storage Unit. This works fine for me. As your backups are encrypted and pass over the line (doubly) encrypted, it doesn't matter whether you trust the backup host at all.