a classy magician would never resort to a hecklers level. there may be alot of fun things you could say, or your typical comedic heckler responses etc. however if you put a heckler down, and become repulsive, or derogatory, what kind of example are you setting as a performer? everyone in the room will question your actual ability as an entertainer.
unless your working in a bar or something, or as chris stated, a "middle school" i really dont see this issue happening often. i been in the martial arts, and magic for over 23 years. magic on and off, but always stuck with the martial arts, and i can say i never really had any hecklers during my shows, and if i ever did, i would never even think about it being an opportunity for me to whoop some A**. the martial arts instills positive character traits, and teaches non conflict over conflict. the more you train, the more self confidence you obtain, and confrontation is never needed to prove ones own self worth, or clear up and psychological insecurities.
your their to entertain an audience, not to lure some low life into a confrontation. unless however you wanna take up "jail magic" and maybe make new tv special out of it. there are clever ways to to turn the rest of the audience on the heckler, and sometimes you dont even have to try. if you do free shows alot, most ppl will assume that is all your magic is worth. if you have scheduled shows in the right environments, you will not be heckled, ever. at least that has been the case for me two decades. if this is happening to you alot, i suggest you change your venue, and the audiences you perform for.
your attitude here seems to be getting you heckled by other magicians even, so it may be time to take a recoursive action, or new approach on your mindset about all of this. if the hecklers know it bothers you, they may get even more hecklers to stalk you at all your shows. they will want to be everywhere you go just to make you more angry. however if you would have ignored them in the first place, or handled it politely, not only would the audience respect you more, but i am sure they would eventually grow bored of heckling a non responsive performer. if you want to truly excel at this art, you will make changes, whether it be your environment, your attitude, or whatever is necessary. make them play your game, dont play theirs.
a clever magician uses his mind to overcome adversity, not his fists.