For me, not in system folders, it's logic.
mGalaxy have nothing to see with the system, so not in c:\user not in c:\windows not in c:\program file.
For me, never in c:\ to be simple.
When I have problem, I can just format c:\ and reinstal new system. I just need to make "profile backup" for apps that try to be "conform to Microsoft recommandation" and save setting in folder where no one never go.
I can use external harddrive and switch them beetween machines without problems.
I realy like all that can work in portable mode, all in same folder, I can understand somes applications can't work 100% portable mode because they need to interact with the sytem, but for an emulator ...
Warm users is useless, you need to prevent him if you want to avoid problem.
But I m an extremist about that. not a reference ^^.