Someone would stay with XP , someone have really not had any problems with Vista .On the other hand Linux is free and there are so many versions of it, media, server etc. In it's modern state, Linux is ...
I like Linux because it's more secure and currently has a graphical user interface that puts it out ahead of Windows and Mac OS X.
However, while it is nice to not have to pay for anti-virus software, or .........why you like to stay with Linux ?