when you buy a PC / laptop, approx £50 goes towards an OEM licence, some people dont like windows, i find it ugly, and in most ways impractical and slow. a LOT of linux apps are ported to windows BECAUSE loads of people use them.. but here is a small example of a few costly windows spefic apps, and their linux counterparts..
Windows - £50+
MS Office - £150+
MSVC.Net - £300+
Now, some KDE Alternatives..
KDE - Free
KOffice - Free
KDevelope - Free
People switch, because they would rather have a free application which does the same job as an expensive microsoft product, hell, theres even a Visual Basic alternative for Linux / X (Gambas (Gambas is AlMost BASic)), there is the issue of illegal copies of programs.. but some people feel guilty, there are also a lot of 'call home' features now being implemented into MS products.
As another note, have you READ the EULA for Windows XP? i'm not sure if MS changed it, but recently, they made a change that said they could come and repossess your PC, whenever the hell they wanted too, people who read the EULA get scared of shit like that
