For a couple months, i was having all kinds of hardware issues with my main rig and was forced to use my server while I was diagnosing the issues. Server is running Win2k3 server and honestly? I found it to be a very peppy and stable desktop OS. I turned off all the server services, enabled all the standard desktop-related services that are disabled by default, and other than reporting that it was win2k3 server, it was just like XP... only it felt so much faster and peppy. I never used this utility, and basically did most the what it provides manually.
There are times with XP where the system just sits there and chews for a moment, then comes back to life. I'm so used to this behavior (even win2k pro had it) that I don't even notice it anymore unless i'm trying to get something done quickly. It was actually noticeable that this behavior was missing under win2k3 svr.
Hearing that Vista is based on win2k3 svr SP1 kernel, though very much tweaked, it gives me hope of the potential of Vista.