Which sensors do you really use?

[HighLife]

On the AdamBots FRC robot we are currently using the kit hall effect sensors mounted in the transmissions for distance measurement in hybrid. We are also using a yaw sensor to give us the heading of the robot in hybrid and we even have a one joystick drive mode based on the heading given to us by the yaw sensor.

On the fun side my dad just bought me a PIR sensor today. I'm probably going to use that to wake my robot up when someone turns on the lights or something like that. There is also SONAR sensors that I've used to judge the distance of objects like walls and table legs. I've also used an IR sensor for line tracking with lego robotics.