DR is the process and planning of the recovery and continuation of the system/enterprise in the event of a disruption to service with the minimal loss of data and the least down time. This can range from a simple server failure to the loss of an entire building due to fire. I wonder how many backup tapes still live in the server room next to the server. Does your DR plan allow for the theft of your hardware, including the backup tapes? Ask how you would cope if you arrive to find all the media,cpu's and memory stolen from your server room.

It is the planning and testing of these processes that constitutes a DR plan, not just having a backup for the last 7 days. The best quote I know is "the only good backup is one that has been successfully restored" no DR plan is a plan unless it's been tested, scenarios may range from a simple restore of a backup to restoring the enterprise in another building.

As mentioned above the business has to calculate how much data loss/downtime it can stand ( vs the cost ) and the DR plan has to allow for that, for all eventualities.

Although I hesitate to mention terrorist activities, we suffered a few attacks here in the UK, a colleague of mine had a backup strategy etc. etc. but after a bomb attack they were not allowed back into the building for several days so could not get to their "everything proof" safe to get the backups out. That's a simple example of DR planning.