Intense speed. Graphical rendering seems effortless, and that has a huge impact on perceived usability. Where Windows labored to bit-blit (combine two bitmap) images before, it now draws in fast motion. The result is crisp curves and fine lines that rapidly appear across your screen. The difference is palpable.

Reliability. The new Windows Display Driver Model (WDDM) has changed the way that video drivers access core parts of the operating system. Video drivers no longer have such intimate access to the Windows kernel. There's an abstraction layer; the use of DirectX 9 is required for the highest video support level. Only a small stub of an instruction set is permitted directly from the video driver to the kernel. And that means that blue screen of death (BSOD) will be reduced by a huge factor, since something like 80 percent of such events were caused by video drivers in earlier versions of Windows. To give you a real-world example, since last September I have not seen a single BSOD on any of the six or more test machines where I've installed Windows Vista.

Subtle UI improvements. It's easy to be skeptical about this aspect because the advantages literally slide beneath your level of awareness. The fact that you can see one window behind another because part of the covering window is transparent makes you feel less closed in and more aware subconsciously about what you have to do to reveal something else you want to work on. Shadows and reflections make the world you view on your computer feel less antiseptic, less fake, more like what you expect from the rest of the world. Again, the user experience is just a little better as a result. Add these things up, and they may just present an OS that's a little more fun to use. For Windows, come on, that's saying a lot.

Next to the security improvements, the powerful graphics subsystem is likely to pay the most dividends Vista users over time. The improved experience will grow slowly, but it will be evident in future applications.

8. Start menu