Business Continuity and Disaster Recovery
It's important to ensure that the virtual desktops along with the application delivery infrastructure is included and prioritized as a Business Continuity and Disaster Recovery plan. Also, it's important to ensure that the recovery procedures are tested and validated on a regular cycle, as well as having the procedures and mechanisms in place that ensure critical data (images, software media, data backup, and so on) is always stored and ready in an alternate location. This will ensure an efficient and timely recovery.
It would be ideal to have a disaster recovery plan and business continuity plan that recovers the essential services to an alternate "standby" data center. This will allow the data to be backed up and available offsite to the alternate facility for an additional measure of protection. The alternate data center could have "hot" standby capacity for the virtual desktops and application delivery infrastructure...