Tug & Melody,
The bullies of today are on a whole, perhaps more vicious than in years gone by. Violence, well, it never changes... but the social aspect does. Society now frowns on the victim responding with violence, meaning that the victim is further victimized for standing up for themselves. Meanwhile, the bullies are treated with kid gloves because they have special needs (which are the source of their bullying behavior).
The truth is, there are many reasons that children start acting as bullies... substance abuse, mental issues/disabilities, lack of self confidence, innate anger issues, abusive or neglected home life, trouble with school, or just because they are psychopaths (I think this last one is increasing in numbers, btw). Lastly, kids... following human nature... are very quick to figure out who/what is different and ostracize that person for it. That, perhaps, is the only thing we can strive to change in the school setting... everything else requires much more intensive work. FYI, all children are essentially amoral until they've had our morale precepts ingrained in them via social bonds, education and constant reinforcement.
As much as throwing a punch feels good... it's only as good as long as your victim (sorry, your bully) is afraid of you. People get much braver in numbers, so all it takes is an escalation of violence to restart the bullying cycle. It's why bullies hang out in groups of 3 or more now... they can't stand a one on one fight where they might lose. We used to think swarm beatings were isolated to certain immigrant cultures, but that was nothing more than ignorance... it's an increasing form of violent bullying that must be combated with something else other than escalating violence.
Also, fists have no effect on social bullying... the only way to fix that is to destroy your bully using the same tactics, victimizing them by cowing all of those that look up to them...isolating them... driving them to humiliation and hopefully self harm. At which point, you're no better than them.
As far as people standing up to bullies, it really depends on whether you're an extrovert or an introvert personality. The extrovert will throw that punch, fight... the introvert will shut the door and retreat inwards to try to block out the attacks. Neither is truly and effective method, but it is what children do when faced with this sort of things... as adults, we should have more avenues of communication to deal with it (not that it always works, but that's another story entirely).