To answer the question "Why is a weapon my first choice"
Without getting into a huge gun control debate (what's even the point?), I have been a "weapons" fan for over a decade, owning several firearms, knives, and even a couple of cool toys, such as really powerful hand held lasers (I have a 2W flashlight sized blue laser, which will light matches and pop balloon immediately, and burn thru most plastics in seconds) and even a sonic cannon (will generate a sound up to 140db at adjustable frequencies and will scare the shit out of any backyard pest)
In short, I believe in self defence, and I believe in making it as intimidating as fuck, and at the same time as safe as possible.
Even if I load really soft rounds on my 12 gauge (like 7 1/2 birdshot let's say), a potential thief would probably not receive a lethal hit, but he'd sure fucking bleed like gushers and permanent scars might be left, and worse, he'd probably still come lunging at me or my family. The only way to "stop" him, is most likely to use more powerful shells that will likely "stop him" forever.
Firing my laser at him would be intimidating as hell (picture a bright blue beam being fired at your chest) but not likely to do anything. If he is armed and insists on coming towards me, only option is to fire at his eyes and permanently blind him. Not acceptable.
A perfect phaser as depicted in Star Trek, on the other hand, would be an excellent non lethal weapon. It would have the incredible intimidation factor of seeing a huge motherfuckin' energy beam being fired at you, capable of completely disabling the perp, with the added bonus that he is extremely unlikely to have suffered any permanent damage at all.
I'm not sure if that is ever going to be possible, but for what it represents, I think it's an amazingly cool technology that I'd love to have.
Flying Cars would be as safe as Helicopters and Planes are, once they get a viable technology mass produced, but I admit true "Delorean style" flying vehicles are not likely to appear in the next 40-50 years, except with very niche organizations (Police, airports, high end transportation?)