We currently use Symantec 10d, but this month will be moving to Acronis True Image Server with Universal Restore. This means we can restore a server image to any hardware (doesn't have to be the same setup as the original) whilst getting a dead server back online, and if we want we can also restore to a VM and run the server normally.

Managed to get a good discount from Acronis. Of course it also backs up normally, so it isn't just imaging software.