Banning guns isn't going to reduce organised crime, thought out murders, etc. As people have said, if a person wants a gun, they will be able to find one, legally or illegally. What it can/will stop is the more rash murders, spur of the moment stuff. Husband walks in on wife sleeping with another man, heads straight for the draw, pulls out a gun, boom. Car cuts another off causing an accident, offended driver pulls handgun out of glove compartment, boom. Hell, thief breaks into a house, resident pulls a gun on him, taking the law into his own hands instead of calling the police, boom.
Banning guns doesn't make guns unavailable, but it does make them LESS available, and that leads to less gun crime, as only those who really want a gun will get one.
And the argument for being safer if you've got a gun is bullshit. Just say a burglar breaks into your home, and he's got a gun. You don't realise this, and confront him. He points the gun at you. Now, if you're unarmed, he's probably going to go about his business and leave you unharmed, he's just here for the loot. He might tie you and your family up or something just to be safe, but he's unlikely to hurt you. If you've got a gun, however, bullets might start flying, and that doesn't benefit anybody.