I have a laptop that runs XP, I'm unlikely to upgrade it until it dies. I don't do anything on it that requires a newer OS, so not sure why I'd pay the $$ to upgrade until I get/need a new laptop.

I still run XP and 2k. I need it to support hardware that does not have a 64 bit driver. (It might be possible to run under win7 32 bit, but I've not tried.)

Institutions and China. ~60% of our lab computers run XP because there are software packages that we use that are broken under Win7+