The starting point for a rock solid disaster recovery (DR) strategy is to establish what the true cost of server/platform downtime would be to the business.
The project will require you to collaborate with your key business decision makers and you will need to communicate to them what the associated costs of downtime are and what the business impact would be. You will likely need to collaborate with several business units in order to gather the required information and collectively you need to come to a decision as to what is considered acceptable downtime for the business. Only then can you begin to devise a DR strategy that is appropriate.
You will also find that conducting this exercise may highlight shortcomings in your platforms current configuration with regard to high availability and this may also need to be reviewed as an aside project.
The key point to take away from all of this is that the decision as to what is an acceptable period of downtime is not for the DBA alone to decide but rather to provide the information and expert knowledge necessary so that a realistic decision can be reached. Your task as a DBA is to design and rollout a DR strategy that can accommodate the needs of the business.
Do not forget to test your DR strategy by conducting a test scenario in order to validate your recovery times and to practice the overall process. Should the time come when you need to implement your DR strategy you will likely be under pressure, your phone will be ringing frequently and people will be hovering around you like mosquitoes. Having already honed and practiced your DR response, you can be confident in taking control of the situation and implementing the recovery will be a smooth process.
The following article may assist you in getting started along the right lines with your DR project.