Do you remember the good old days of 2004-2005, and to a lesser extent, 2006? Way back when there were forums bursting of people dismissing XP completely and holding onto Windows 2000 Professional as if it was the elixir of life. It's exactly the same principle, and I mean exactly the same principle. People complained XP was bloated, sluggish, irrelevent, and now look at us, we love it! Can't get enough. Vista is a bit OTT, granted, but in a few years the situation will be the same. The only issue I have with Vista is the one you have brought up, its speed, but if you run it on adequate hardware and give it a couple of weeks tops for it to index stuff and settle down, it speeds up over time rather than slowing like XP does, making it the better operating system. Anyway, to answer your question: services, DLL hell, UAC, DRM. My beloved S2k8 has all of these, but no DRM, which results in it being about as fast as XP. Vista is far better than XP though. Of course it doesn't come close to Server 2k8 when configured as a Workstation. Try it.