More information can be found here: http://www.zdnet.com/hell-no-we-wont-go-10-reasons-some-xp-users-refuse-to-upgrade-7000026539/
I never understood what the big deal is -- the big scare about XP becomiing vulnerable to malware, etc. I mean, it's not as if other companies are no longer supporting XP -- Symantic/Norton, McAffee/Intel, Eset/Nod, Malwarebytes, Avast, etc. And even Microsoft has decided last month to have Security Essentials/Defender continue updates for XP indefinitely...
The only reason I can see for running XP is when running older hardware. There are several people I maintain installs for, some of whom are/were adamant that they wanted nothing but XP. On the XP computers I installed various malware progs, AV's, etc. On the Win7 PC's I hardly installed anything, maybe a lite running COMODO. Guess who call me constantly and who don't. You guessed it because deep down you know it XP users called me again and again because their installs go haywire. I do think if you're savvy you can run any Windows OS (well, except maybe ME lol) and it be fine for you. But for regular users I would not recommend XP anymore. The compatibility where it comes to drivers is also impeded in the XP scenario and newer hardwares. I think the current question isn't so much anymore "why would I change from using XP?" as "why are you still using XP?"