Always been a fan of server virtualisation, simply because of the portability of virtual servers once they have been through the virtual infrastructure sausage machine.

Data Center contingency becomes much easier, its a case of finding the most cost effective way of replicating the virtual servers from storage solution to remote storage solution and then providing the host hardware to run those virtual machine when the shit hits the fan (usually there are network routing and DNS issues to deal with too but hey, it doesn’t half make things easier once you virtualise)

Data replication though, it can be expensive stuff, so can the redundant hardware needed on the remote site, awaiting activitation when a ‘plane lands on your data center’ (not sure how many times that has happened, but always seem to be the number one threat when having discussion on the subject).