Now, to jump into Greg and WAMO's debate...
On one side, I get it. Cowards keep using guns to kill innocent people, so people get scared and want to think of ways to stop the bad guys because, well who knows if I'll be next to cross paths with a homicidal psycho? Basically, mass shootings are terrorism, plain and simple. It's just that in America terrorists predominantly use guns instead of IED's/homemade bombs.
Greg has good points too. Prohibiting guns is risky, because this country doesn't exactly have a successful record enforcing prohibitionist laws and eliminating the behaviors that were expected to be curbed by such legislation. Look at prohibition - it merely made petty criminals of otherwise law-abiding citizens who just wanted a beer, and also fueled a massive underground crime ring that profitted from providing illegal booze. Same thing happened with the "War on Drugs". So I'm skeptical about banning guns - my fear is that just like with alcohol and booze, there will be a massive increase in illegal underground gun smuggling activity. These dealers will make the whole situation much more dangerous than the risk we take with Wal Mart accidentally selling a rifle to a nutcase.
I'm not sure the perfect answer exists. After all, as Greg pointed out, human beings have a consistent track record of killing each other throughout history. Even without guns cowards and terrorosts will find a way to efficiently and effectively kill people. It's been happening since the beginning of humanity on earth (maybe before?)
On edit - Another nod to WAMO's point; just because we've failed in the past doesn't mean we should accept it as it is and stop trying to strive towards a better solution. Humans have a spectacular history in resolving problems - if not, we'd still be riding horses and averaging a 35 year life span. We've gone to the moon and beyond. Surely we can figure out how to create and maintain a successful, safe society?