Definitly leg strength, just look at naseem hamed, he was a tiny even for a featherweight, but his legs were like tree trunks, he would punch crouching slightly so he could put all the power from his legs aswell as his arms in punches, his power was devestating. Compare that to someone with a big core like most of the overweight heavyweights we see today.

http://m.youtube.com/watch?v=lLXcgZ84ndk

Both, let's take Iron mike for example. His height was about 5'10" prime weight: 228lbs he had to use his core and legs to explodes on his punches because the guys he Knockedout where 5'11+ but this way he could come under neath him which is easy for less movement. His uppercut was all legs all. Hooks legs and core.

Strong legs definitely but also a strong hip will help channel the power to your core and into your hand

Like in baseball, golf, etc. It all starts in the legs and works it's way up through the rotation of the hips and shoulders through the arm. all are part of the procedure, but it starts in the ball of the foot and the legs first.

I THING LEG STRENTH, BUT A STRONG PUNCH COMES FROM BOTH AS THE KENETIC ENERGY BUILDS UP THROUGH YOUR BODY, I PERSONALLY THING GOOD LEG STRENGTH MAKES FOR A MORE POWERFUL PUNCH THOUGH

just somethin' I'd like to know. I mean I know leg strength an' core strength is very important for punchin' power, but which one is more important?

please do us both a favor an' dont waste your time talkin' about technique....I already know how important technique is.