The Lock Master
Gary, I read the lock hacking bit, and I was surprised at how simple the method was. It's so obvious once you know it, I'm a bit mad at myself that I never realized this years ago. Converting an m^n problem to an m*n problem simplifies things wonderfully.
Of course, once you come to the hack, the next question is how to prevent that exploit. The main way I can think of is to find a way to tie the pins together so that they will only open when all of the pins are set for master or all set for the lock-specific key. This solution would probably lower the number of possible keys, as well as making the locks more specialized. (One advantage of the susceptable master keys systems is that they can be made from regular single-key systems).
Of course, I'm having trouble finding key blanks which match my dorm keys online, and I don't want to walk into a hardware store comparing random key blanks with a key stamped:
U of M
DUPLICATION
PROHIBITED