Windows (Vista or XP) is actually fine, it's the lack of good 3rd party apps that kills it for the home user

Thanks to lifehacker for putting together such a good list of 3rd party software to use on Windows:

http://lifehacker.com/384545/superior-alternatives-to-crappy-windows-software

The reason why I love Ubuntu (and Linux in general) is that you can install most of the equivalent apps with a single command line operation. This alone would keep me using Ubuntu, even if I ended up buying a Macbook Pro.

Microsoft: Stop making crappy apps and bundle the good stuff with your OS (or make it easy to install them). Small groups of hackers have made great software that they give away for free. Help out your customers and help them get it without having to be nerds.