Vaccano: really the "problem" is that XP was already kept running longer than it should have.
look back to the "Longhorn reboot" and the push to get the huge XP service pack out.
while at the time it was the right thing for MS to get the security fixes for XP out it also meant that the release of what became "Vista" was much delayed. so really Vista and WIndows 7 were both late getting out and many folks got locked into the XP OS far more than they should have.
while i have my own concerns with the upcoming WIndows 8 i do tell anyone still using XP they really need to update unless they have a very very special case and then they should not look for new features, just maint on old code.
when windows 95 came out it was the end of the windows 3.1 era.