Like Nick says, an external drive is peanuts.
If its business data (or irreplaceable personal data), regardless that you are in a home office, get it saved off site.
This can be leaving an external disk once a week with Frank 5 doors down, Mum, a mate, or online backups with a 3rd party.
In this day and age, with so many low cost solutions theres no excuse for data loss. IMHO
