HAL probably did, and no matter what, sometimes a computer just becomes corrupt for no reason, and, in the case of HAL, such corruption can have deadly consequences.
Dave probably did the best thing possible for HAL: shut him down (in effect, "killing" him), because he (it?) had a confused mind and couldn't think straight anymore.
Anyway, back on topic (at least for me):
A multi colored LED sounds interesting. If the thing had a sleep mode (I'm sure someone will do it someday), perhaps it could change color (say, from white to amber) to indicate the machine is asleep.
Meanwhile, my opinion is to keep it simple for now. A single color LED is much easier to just plunk in (since the circuit is designed for such a device anyway).
c