Seems to be the flavour of the year this...
Things to consider...
Hard/Soft copies of Infrastructure (Servers, Applications, Interfaces)
A war room (Where you can meet if a disaster occurs and have a copy of above)
Or are you looking for the more technical aspects?
Depending on the size of your organisation, having a backup storage facility located somewhere else around your site (possibly remotely depending on data volumes) is a sensible consideration.