I love running the highest performance, most stable OS Microsoft has ever produced on my desktop. The problem: a lot of the features that make a sense for a server OS, make little sense for a desktop.
An example is the Display Shutdown Event Tracker. This feature is pretty self explanatory--a great way to track what is causing reductions in uptime. For my desktop, which I reboot often into Longhorn, it can be a bit of a nuisance.
Group Policy to the rescue.
This should only be done on systems where tracking up time is not necessary.