I think free breakfast is what the hotel should give you if it's not their fault. Little cost to the hotel (I'm talking continental b-fast here) and would go a long way to soothe most customers. If I were in that situation, it's about what I'd expect.

To expect monetary compensation (or cash discounts on rooms) is a bit much. You can't expect the hotel to take a big loss because of some punks who decided to rip the fire alarm. Now if the punks rip the alarm 3 or 4 times in a night and nobody does anything about it, my opinion would change significantly. Then I think I'd refuse to pay for that night's stay.