1. By the year 2015 a lot of people will have heard of Linux and are opting to try it out.

2. within 5 years...

3. Conservatism... you know what you have but not what you get. I think it will mainly be a generation thingy. So personalization is important.

4. Ubuntu.. no one els is as stable and complete. And it's easier than Windows. Got my brother to try it out when his Vista died for the second time. I put up a dual boot with Ubuntu and Win7. I showed him the basic stuff.. Now he want me to uninstall win7. Just haven't had time to do it.

Windows will be free of charge eventually and so the office package.. but in the long run it will fail. The browser war is a good example of that. Freedom, extendability and personalization is the winner there.