Which sensors should be used throughout the robot?

[thatprogrammer]

Note: This is in response to a disucssion I had with 971's technical mentor, thanks for the help!
I've been wondering what sensors are the "best" for certain areas of the robot. The areas I'm thinking of are: Fly wheels, Elevators, turrets, and drivetrains.
What different sensors have you used for these applications, and how have you found them?

P.S. Has anyone used the S4t? Am I right in my assumption that it doesn't rotate?