Catastrophic Hardware Failure Recovery With Exchange 2003 :

Recovery from Loss of Node
Evict the old node and verify eviction
Build a new cluster node and join cluster
Restore System State only on new node

Install Exchange on new node
Install same Service Packs, Hotfixes and Rollups that were on failednode
Make new node Possible Owner of resources
Recovery from loss of Shared Storage
Replace lost storage
Make sure disk signatures are correct (MSKB 305793 and MSKB 280425)

Recovery from Quorum or Quorum Log Failure
Use DumpCfg to recreate disk signature (MSKB 305793)
Perform a node system state restore
Use ClusRest to restore quorum from backup folder
See MSKB 245762 and MSKB 248998 for more information
Use Server Cluster Recovery Utility - clusterrecovery.exe (WindowsServer 2003 Resource Kit Tools)


Recovery from Total Failure
Rebuild all nodes
Create original cluster group
Restore System State on each node
Install Exchange on each node
Install same Service Packs, Hotfixes and Rollups that were on failednode
Recreate Exchange resources (use same network name resource) Restore databases from backup

Check out http://microsoft.sitestream.com/TechEd/MSG/MSG344_files forSasha's presentation, and check outhttp://microsoft.sitestream.com/TechEd/MSG/MSG348_files for mine.