That seems like a good price for rotors, pads and labor from a BMW dealer.... perhaps we are more used to abuse down south...

Is your brake pad warning illuminated?

If your rotors measure OK (ie less than 50% of the allowable wear) you can skip rotors. Otherwise you run the risk of wearing the rotors past the wear limit before the pads wear out (and the sensor is tripped). Since I basically monitor pad and rotors independently, I'll change each when they are needed....