Setting up something like BackupPC is fairly easy and would give you copies of the production system in the event that it has issues. Backups are not optional. Remember to test your backups regularly as well. Never rely on an untested backup.
The real question is how to handle recovery. Many people want to have a backup system that just automatically takes over if the primary system is down. This is very hard and if done wrong will probably lead to downtime rather than preventing it.
At the other end of the spectrum, is just having a copy of all the data so that you can recover the production box (or some sub-section of it) in the event that it is needed. This is easier to setup, though obviously you may have hours of downtime as you recover the data and get things set back up and tested for production.
If you have databases, don't forget to make sure the backups get consistent copies of this data. I tend to just do a "dump" of the data daily to a file and use that for backups, some people prefer to back up the journal files for re-creating the databases, or use snapshots to get a point-in-time copy to backup from. For most of my own uses a dump is fine and the simplicity wins out.