System Stability Chart in Longhorn
If you go to the Computer Management tool in Longhorn (Dec CTP), then you will something called the System Stability Chart, which shows you how stable the system has been including Software Installs/UnInstalls, Failures (including Apps, Drivers, Hardware, Windows), etc. Its pretty cool and should help narrow down cause of failures - quite helpful in a corporate environment.
Here is a screen shot from one of my VMs.