Frankly I see Microsoft's push to release a new OS this soon after releasing Vista a big clue that they were met with a great deal of opposition towards the new OS. It's a basic bells and whistles update to XP just like ME was to 98. Granted they might have cleaned up some of the core libraries and bits of the kernel, but it's still a glamorized XP.
Personally I'll never switch to Vista so long as I have a choice from PC manufacturers. My preferred OS is and always will be Linux, specifically Gentoo for it's development tools and flexibility. In a world where everything is becoming more expensive by the day, a free OS that's fully featured and customizable is the best thing there is. If Microsoft hadn't cornered the friendly OS market and made sure everyone made their drivers through iron clad contracts and licensing fees Linux would probably be on top of the computer industry. It's free, it's fast, it can be modular or seamless, it's functional, it's adaptive, it's clean, and the support communities out there for it are massive and informative. What more do you need?
I use Windows for very little beyond web surfing at work. It's a great OS if you don't want to do anything productive, aside from spend lots of money of course.