The way I see it there are generally 4 or 5 types of punchers

1. Feather fisted, these guys just dont have much punching power whether it be due to poor technique, being afraid of committing with their punches or just having no power.

2. Heavy Handed guys, these guys usually naturally have a good bit of weight behind them, denser and heavier bone structure, they might not have one punch knock out power but they sure knock you about and wear you down. Their punches are more like clubbing punches that do a lot of damage but because they are heavier and generally slower they might not be able to generate the velocity needed for a knockout punch as easy as some other guys.

3. Sharp punchers, these guys are not naturally powerful but their punches hurt because of accuracy and technique, whereas the heavy handed guy's punches feel like you are being clubbed to death, the sharp puncher's shots sting.

4. Explosive punchers, these guys might not be as big as heavy handed guys but they can generate alot of speed and force in their punches, alot of the time its just a case of them having the mentality of going for the knockout and committing themselves on every punch.

Thats just my view of things anyhow, heavy handed in my opinion doesnt always mean the guy is a knockout artist or anything....for example I would consider Antonio Margarito to be a heavy handed fighter, but he doesnt have the sort of explosive knockout power of someone like Pacquiao.