I am a computer savvy user who used Linux as my primary OS for several years (I switched to Windows for reasons I won't specify). If my university didn't provide Windows 7 to me for free, I'd still be using XP. It's a perfectly usable OS.
Since you didn't specify the reason of your switch, I am going to guess ;)
I think you switched because your university doesn't support Linux :)
On a serious note, at my workplace few people are still using XP when they are free and encouraged to upgrade to Win7, then I guess some people out there are just not willing to change.
