Hi DrHoy
I believe that most of what Jimmy has said is true but it is not the whole story and rather waste time considering what Microsoft wants you should spend your time thinking about what you want and need.
Now, if you want to use the latest computer technology along with the latest software then by all means get Windows 7 or, better still, get Windows 8, which is on the verge of being released.
However, if you have older applications that runs under Windows XP (Pro SP3) which you use to run your business, i.e help you to make money, or is required to organise certain aspects of your personal life then upgrading to Windows 7 or 8 is a much more daunting problem.
For example, I use a piece of software called MightyFax, it is no longer being made or supported. However, I still find this application extremely useful, especially when communicating with organisations that do not use (or allow) external emails.
There are also other older applications I use which would not run under Windows 7 or 8 and that for me is the most important thing. You see, I did not buy my computer to play games or marvel at it's new found technical ability nor do I want my computer's operating system to be the centre of my computer usage. Instead, I have a number of practical tasks I need my PC to carry out, e.g faxing, emailing, personal Information management, etc., not only for myself but for my extended family as well. Therefore, I will not jeopardise the practical functionality I have now for the latest bells and whistles on a new O/S.
At the moment, I see "no rhyme or reason" to upgrade to Windows 7 or 8, while knowing this will break my current applications, which are constantly in use, and leave myself running around trying to buy updates or alternatives for the applications I already have.
However, I will admit that at some stage in the future I will have to buy, or assemble, or new computer which will not work with XP, then I will have to buy a whole new collection hardware and software (which is what the industry wants) but I will only do so when I have absolutely no choice.
UK Bob