How far should you be from your closest data backup?

Question

Pretend for a moment that something catastrophic happened; you're hacked, and your production database becomes a mess.

How far (time) should you be from your rolling out your latest backup and resuming operations as normal?

Of course, "immediately" is "ideal", but I'd like to see some real answers. Perhaps some existing, real-life situations that you're currently in with regards to backups.