Which exercise will help increase punching power?

anytime you make a change in how you work out... the muscles you used to use will fade, and you will strengthen different parts.... it is really a dilema we all fall into when we learn new things... "I used to be able to do this, but now I can do that" I dont think there is really an answer, unless you are 20 years old, filthy rich, and still find the desire to become they perfect speciman... (we all have to work for a living... damn the bad luck)