The URM ultrasonic range finder by DFRobot is a nice one. Good distance (~10cm upto 3~4 meters).
You talk to it over serial, but it offers digital triggering and even interupt triggered response (it will pull a pin high when something comes in a pre-set range).
Also, it is able to control its own servo when used through its serial interface.
I love this module to bits, the one I purchased was around $15 USD, so it appears to be on the same price level as the ping sensor.. just has more fun stuff.
PS: it is also capable of making temperature measurements, though I haven't been able to find out what type of values this returns.