Online backup is important. We use Arq a lot for this as we are in control of our backup destination. If you have some webspace available or you have an amazon S3 account, you can route your backup there. You are in control and you have the account with storage provider, not some middle man.
Of course in addition to time machine or some other software. You never have enough backups!
Also good is to have an external disk where you clone internal disk to, so after a disaster you can boot from external disk and restore newer files.