What functions are restricted to administrator accounts?

OK, to keep me from banging my head against the wall any more than I

have to, can anyone point me to a definitive list of those things that

are restricted to administrator users only? Not those that are

restricted to administrator users by default (although that would be a

nice list to have as well), but those things that there is no way to

assign to a non-administrator.

Regards,

Dave