Or leave it on to maintain a bit of security and knowledge about what other programs or virii are trying to do to your machine.
ALL other OSes require user intervention to perform admin level duties. Yes, YOU are the admin, but you do NOT need to be running AS admin 24/7. That's the very reason windows is so virus ridden. Count yourself lucky you only have to click "Ok" and not type in a password.
People that turn UAC off are analogous to people that refuse to give their kids innoculations based on hokem science and endanger then entire population. Do it for yourself and do it for the Windows universe. Leave UAC ON.