Although it's obviously limited to media files, iTunes Match has probably the most elegant solution to the problem. CrashPlan is also doing a great job for backups via constant syncing with the cloud.
Backblaze is OK. $5/month for unlimited backups is great, but have you ever had to use their web interface for restores? Argh, its horrible. Also, it doesn't allow you to backup your Applications directory on your Mac. WTF?
