Originally Posted by Blue 
There's more functions than stalling software that you can't do from an un-privileged account though.
For example?
Anyway, that's why in Vista UAC was introduced. Even in administrator accounts applications run without administrative rights. If some application requests administrative rights, user is informed and he can allow or dissalow for application to grant such rights.
This is good security measure, however most ignorant users hate it and turn it off...