I think that only some weapons should be banned. Howitzers in the back yard, while cool, are exceedingly dangerous to both the owner and everyone within range...which would be a lot of people.
In America, where I live, the whole point of having weapons was to defend ourselves from criminals, the government if we decided that they needed a boot to the head, and whatever pesky people might decide to invade/attack us (this goes back to the frontier/border regions).
I have no problem with rifles and/or shotguns. I prefer rifles personally, but that's neither here nor there. My problem with guns mainly comes from handguns. There's no reason anyone should really feel the need (unless they're in law enforcement and all those branches, which includes judges/attorneys) to carry around a handgun. We know that most crimes that involve guns involve handguns because they're easily concealable. Even as a home defense weapon, handguns aren't all that great because unless you get lucky or practice often, you probably won't hit them.
Also, nothing scares someone quite like the distinctive noise that a shotgun makes when you cock it. If they don't bail after hearing that noise, they either have a death wish, are deaf, or are stoned/drunk off their ass. That's when you point and squeeze off a round of buckshot at them. Unless you're aiming in completely the wrong direction, you'll hit them. And even if one pellet hits them, it's enough pain to make most people leave.
Automatic weapons follow more or less that same idea as the howitzer. Unless you've had a lot of practice, all you're going to do is hurt yourself or someone you might not intend to hurt. Most people can't even keep a semi-auto weapon within a target after a series of three or four shots in rapid succession unless they've had some practice.
Then again, I'm all for one shot kills, so if someone wants to mess with me, they'll either meet a rifle, shotgun, or if I do give in and buy a pistol, either a 10mm or .45. Really and truly, it doesn't normally take more than the cocking of a gun to scare most people away. If you must shoot, make sure you're hitting them with something big enough to keep them down, or hurt them just enough to not want to mess with you anymore.